Dear Mr.
Goemans,
It's been a
long time since I have written to you and hope everything is fine with you.
Anyway, I have just setup a 48" x 18" x 18" plenum system just
two months ago and everything seems to be fine, except for a recent algae
problem on the sand surface. I siphoned out the top layer of sand particles
last week and things now seem much better. But there are a few questions that I
would like to ask and hope you can find time to reply.
1. You
mentioned in a previous mail that I should siphon out the top layer of algae
covered sand particles as often as possible. That will reduce the depth of the
sandbed. The question is, do I just wash those sand particles and put them back
in or should I just dump it and replace with new sand. If to be replaced with
new sand, how should the sand be treated before I add it. (new sand = no
bacterial = need cycling = ammonium peak on the top layer = algae problem
again?)
2. My nitrate
is now about 12mg/l (nitrate-nitrogent) does adding more sand and live rock
helps to reduce it? If so, how much.
3. Is the use
of UV clarifier advisable for a plenum system?
4. There was an
article in FAMA (August issue) saying that a NNR system will not work in a
closed system unless it's a semi closed system. Does that mean my system will
fail eventually?
Hope the above
questions will not take too much of your time.
Best Regards
Stanley Tan
Singapore
Hi Stanley,
Thanks for the follow-up and things here at home are
fine, but things in our country could be much better! Why can't people just
help other people, no matter who they are, have a better life?
To clarify for the readers
of this column, what was said was to siphon out, as necessary, the sandbed
surface algae if it becomes mat-like. With that will come some upper sand
grains that are attached and, that it's quite normal for some algae and/or
cyanobacteria to flourish in any area where light and nutrients reside. That
would include the sandbed side areas facing outward at the aquarium side panels
and especially the sandbed/bulk water interface.
As for your questions,
rinse the sand and reuse it. If possible, place the rinsed sand in some vinegar
over night, then rinse again and reuse it. Any adhered phosphate will be
removed. The forming of some surface algae, whether brown or green during the initial
colonization of the sandbed is to be expected since it's a highly active
microbial zone. The initial ammonia/ammonium present at this interface is
almost always quite high and can lead to the situation described. In reality,
it's really a good sign that the microbes are busy doing their thing so to
speak. The major portion of algae/cyanobacteria should become less and less as
the bed matures. Yet some, depending upon bioload and husbandry practices may
continue. But should not be looked upon as a negative unless it becomes
mat-like. If it does become mat-like then system husbandry, such as
feeding/bioload and/or water quality need to be reviewed, as would be the case
in any style filtration system. As for the cleaned sand, it needs no other treatments
as the top-most surface area is always the most active and/or quickly reestablishes
itself naturally. Try to maintain a bed depth of four inches when using a sand
grain size of 1.0 to 4.0 mm. If slightly larger, go to a depth of five inches.
As explained in my last
letter, too much live rock can result in other nitrogen products, such as
ammonium. Nitrate itself might be somewhat lower, but algae prefer ammonium! As
for now, your bed is still not fully developed, and present nitrate level should
go down in the near future. However, other parameters such as diet, bioload,
protein skimming, sandbed maintenance (vacuum upper inch and check for any
binding) need to be addressed, as they would in any style system. Also, check
the nitrate content in the water being used for water changes/evaporation
makeup.
A UV sterilizes the water
passing through it and thereby kills such entities such as floating microalgae,
bacteria, viruses, etc. Much of that is food for corals. Their use in fish-only
systems can be quite beneficial, yet for reef systems, no matter what type
filtration system, they are generally not used.
I recently met the author
of the article in question at MACNA in Baltimore. He's actually a salesman for
an aquarium product company. We chatted in a polite way and was told that what
was said were the results he had from his try at the plenum method. During the
course of the discussion I mentioned the thousands of very successful plenum
system worldwide, with one now established almost eight years and now better
than when it was originally set-up. However, that and other mentioned
actualities did nothing to change his mind. Hopefully you read Julian Sprung's
column 'Reef Notes' in the October FAMA, where he countered some of the
comments made in that article. Hopefully this answer's your question on system
longevity in closed systems.
If you would like to see some photos of my aquarium,
visit http://www.keysmariculture.com/ and click anywhere on my
name (Ed: or check out the photo gallery section of saltcorner.com!).
Hope this helps,
Bob
Hi Bob Goemans!
I am Danish and
new in this hobby, but have had the interest for many years. I have met people
with many years of experience with saltwater aquariums and have already gained
knowledge from some of the good ones. Have also enjoyed reading your articles
and booklets.
Two weeks ago
we receive the first live and dead sand shipment from the US in Denmark. It is
very expensive, but I have decided to try it. I have been "selected"
because I will start my aquarium from the ground up and maybe also because I am
more serious about this hobby then the average hobbyist and want to try the
plenum method in my new reef aquarium. It is a 450 gallon/1350 liter corner
diamond-shaped aquarium. Because I am the first in Denmark to try this plenum
method and I also want to do it in a way which will also look nice I have some
questions for you. In the front where the plenum stops I have decided to mount
a 5 cm (2 inches) high glass wall secured to the bottom with silicone so the
plenum will fit into this area. The aragonite sand will then not enter the
plenum area. I have then approximately 25 cm (10 inches) to the front glass
where I would gradually (as fast as possible) decrease the sand level to 2.5 cm
(1 inch). Do you think this is OK?
Another
question is: Does the plenum area start at the top of the eggcrate, or is it
the open area under the grid that is called the plenum? Will you clear this up
for me, please?
To elevate the
eggcrate from the aquarium bottom you describe the use of PVC pipe. Do you lay
the PVC pipe horizontally on bottom in long lengths or do you cut the pipe into
small pieces in the right height, which I guess should be between 2.5 3.5 cm
as you describe. This means vertically placed so it stands on the bottom. I
know that holes should be drilled into the pipe.
I also plan to
put 100 kg "dead sand" aragonite and 25 kg live sand in this mix, is
that OK? (remember it is very expensive even in this mix, about $800, almost as
it was gold!) I will buy some more if I don't reach the 10 cm (4 inches). And
do you think it is the best to place the "live sand" nearest to the
plenum or in a mix or nearest the bulk water?
I have in mind
to wash the live sand two to three times in used aquarium water from a shop
before using it. And the dead sand in RO water. Does that make sense to you?
I think
you/those in the USA are a couple of years in front of Denmark when it comes to
reef aquariums. Sorry to disturb you with these questions but I know if I don't
ask the result would maybe not be as good as it could be. And I would like to
show my friends the right way to do it!
Thanks and best
regards,
Torben Høffding
Copenhagen,
Denmark
Hi Torben,
Thanks for your email and
many good questions. As for sand cost you could have used crushed coral and
saved some money. Aragonite is recommended simply because it helps supplement
system alkalinity. The most important aspect of the sand is that it be the
right size sand grains. Once a system is up and running with many stony corals
and coralline algae, aragonite dissolution will not keep pace with their and/or
system alkalinity needs. A calcium reactor should be considered if possible. A
reactor probably pays for itself in the long run and I think you'll find the
system much more stable than it would have been if using separate calcium and
buffer additives.
It appears you do not want
to have a deep sandbed look at the front of your aquarium. By slanting the
depth of the sandbed directly on the aquarium bottom from the barrier to the
front of the aquarium you'll be creating an area that will not have the same
microbial efficiency as the bed of sand over the plenum. Nevertheless it sounds
like the majority of the aquarium bottom will be covered with the plenum and
easily prevent the bulk water from becoming 'too' nutrient rich. This sloping
area should be occasionally stirred to lessen anaerobic areas.
The area under the top
surface of the screened plenum grid is still mostly an open space even though
the grid itself is eggcrate material. Therefore everything below the top
screened surface is considered a plenum. As for positioning PVC pipe, either
horizontal or short vertical pieces can be used. The grid assembly simply has
to be strong enough to support what will
be paced upon it.
Starting the system with
some live sand helps introduce bacteria and shortens the time needed for them
to spread throughout the bed. Since live sand probably contains more nitrifying
bacteria, therefore placing it on top helps to reduce the first ammonia the
aquarium will experience. Rinsing the newly arrived live sand helps to remove
any nutrients that may have accumulated from the time it was packaged. Rinsing
the dead sand is always recommended as that removes a lot of the grit/powder
often found in the bags.
When it comes to experience
with reef aquariums, the United States has been fortunate enough to have a
thriving economy and the availability of many aquarium products at reasonable
prices. Otherwise, the desire to learn is worldwide. I would be very interested
in your progress. Please keep me informed.
Hope this helps,
Bob
Note to the Readers,
Most hobbyists have experienced unwanted algae
problems. Unfortunately I discarded most of Danny's letters, which in the
beginning related a sad story about an endless struggle against algae. His
aquarium was becoming a black hole for his investment in time and money. Both
he and his wife were becoming stressed out and ready to throw in the towel. I
began with responding to some general questions and think those and its result should
be quite interesting.
Hi Danny,
There could be a few
problem areas that contribute to unwanted algae growths. As explained in
previous letters in this column the local water company might be treating its
water with a phosphate compound to limit rust in their delivery system, or your
activated carbon might be leaching too much phosphate. Both can quite quickly
lead to the formation of new algae growth. A deep fine grained sand may also
leach ammonium back into the bulk water and if so, will quickly be used by
algae. So quickly in fact, that you won't get a reading on a test kit.
Hope this helps,
Bob
Hi Danny,
From your last letter it
sounds like the source of energy for continued algae problem may possibly be
coming from your tap water. I suggest you research various brand DI units and
look for one that can boost the pH of the water coming from the RO unit. That's
necessary if you want to take
out the colloidal silica that would normally pass
through DI units that don't first boost the pH of the RO's effluent.
Bob
Hi Danny,
What's left?
Keep me in informed, as I'm really interested in
solving your problem.
Bob
Note to the readers,
A following letter from Danny noted that his wife was
a big user of Windex, an ammonia-based cleaner. Bingo!
Hi Danny,
STOP using Windex anywhere
near the aquarium and/or near the makeup water or water used for water changes!
Don't use this product any nearer than 50 60 feet. Windex is the exact
product another reader had a similar problem with about eight years ago. Let's
see where this goes, and also try a couple of airstones in the tank for a week.
Maybe we have found the cause!
Bob
Note to readers,
Danny found it hard to believe that Windex could be
the problem and thought some of the other corrections might be responsible for
the improvement.
Hi Danny,
Glad to hear things have
cleared up. You can always take away one of the four possible areas of
corrections that were instituted and see if the problem returns. Yet, I would
think the Windex source of ammonia was the cause. People just don't realize how
quickly ammonia is absorbed. Maybe now the wife is happier with a better
looking aquarium and you can now pay more attention to her than the aquarium!
Bob
Dear Bob,
Oftentimes,
many of life's blessings are right in front of our eyes, however, go
unnoticed. In today's world it is so
wonderful to find someone, such as yourself, that is willing to give up their
time to help others. For many months I had what my wife and I both considered
as significant problems. Believe me, the problems were causing MAJOR stress. Several
pet shops agreed that I was having problems, however, said that my wife and I
were being over-sensitive. They routinely replied: "Don't worry about the
problems. They will eventually go away." One person listened and offered
assistance. That was you. Since our last e-mail, everything has been great! No
algae! No problems, period! Even my wife says my tank is gorgeous.
Thank you again
for all your assistance.
Sincerely,
Danny
Many months later…
Hi Bob,
I
hope the New Year has been good for you so far. I've leaned a lot from you and
wanted to occasionally let you know how things are going. My tank is still
gorgeous. Matter of fact, the algae problem is history. I get a trace of green
algae on the back glass occasionally but none elsewhere. Regardless, the tank,
fish, corals, and everything is doing great! I did purchase a new
"used" skimmer during the holidays that really seems to be doing a
wonderful job. A guy in Mobile was in the process of being transferred to Texas
and decided to sell everything in his reef tank as opposed to moving it. He had a great skimmer and pump advertised
in the paper. He had the purchasing papers for both showing they were approximately
6 months old. They both appeared almost new. Even though the skimmer is
designed to be used in much larger tanks than mine, I purchased it and the pump
for a total of $240.00. I then installed both and they really seem to be
working great! I feel like I got a once in a lifetime deal on the skimmer and
pump purchase. In one of your booklets you discuss the need for "dry
foam." My old skimmer NEVER made dry foam, only wet. This skimmer does a
great job at generating dry foam. It is also amazing how much clearer the tank
is with the new skimmer.
Do you use
Kalkwasser in your tanks? I have been using two-part liquid calcium and
alkalinity solutions and would like to supplement the calcium with Kalkwasser.
Therefore, I purchased one pound of Kalkwasser and made a couple of gallons of
mix in a 5 gallon plastic bucket using one teaspoon per gallon of RO/DI water. I stirred the solution using a
plastic stirrer and then allowed it to be motionless for 24 - 32 hours. The instructions
said to siphon the clear supernatant layer off. Since the top of the solution
still had a whitish colored film on it after 32 hours of motionless storage, I
threw the batch away. I made a second batch and it did the same! Therefore, I
haven't been able to get a "clear" batch.
I've also read
that Kalkwasser should have a pH above 12 and if the pH falls below 12, discard
it. I have also read that Kalkwasser solution's contact with air will cause its
pH to fall. Therefore, the pH should be checked routinely. The only way to
verify pH in this high range is to buy a pH
meter! Is this
needed? I haven't found any pH test kits to measure much above pH 8. Do you
know of any? Secondly, if you are adding Kalkwasser at a pH of 12, what keeps
the solution from raising the aquarium pH above pH 8.2?
Again, thanks
for everything and I look forward to hearing from you.
Danny
Hi Danny,
The new year has been
pretty good so-far and it sounds like your aquarium is doing very good. It also
sounds like you got a very good deal on the skimmer and pump. I tell a lot of
my clients that if they can't originally afford brand new quality equipment
then checkout the classified section
In the local newspaper. They might be pleasantly
surprised and get a good deal on some used equipment. But, don't start with
inferior equipment because the consequences could be hobby ending.
Anyway, I don't use
Kalkwasser in my aquarium for many reasons. Nor do many hobbyists that use it
properly dose it. To do so correctly, in my opinion, requires that the high pH
of Kalkwasser be reduced to a natural seawater (NSW) pH of about 8.2. To
accomplish that requires either a sufficient amount of carbon dioxide be
present in the aquarium water or the use of carbon dioxide injection equipment.
If not properly dosed, Kalkwasser "will" have a negative impact on
the carbonate buffering system (alkalinity) because of its high pH.
Since my system is always
high in dissolved oxygen because of very good circulation and the use of a
quality protein skimmer it is always quite low in carbon dioxide. Even dripping
Kalkwasser in at night would be detrimental to my alkalinity and precipitate
enough calcium to turn my plenum sandbed to concrete. So I use a calcium
reactor to resolve all calcium, alkalinity and pH maintenance.
Since the presence of
carbon dioxide is usually quite limited in most reef aquariums its impact on
lowering the pH of incoming Kalkwasser is often quite inadequate. Even if a
Kalkwasser solution is dripped into fast moving water at night there may not be
enough carbon dioxide to prevent a major precipitation of buffering agents and
a high increase in system pH. In most applications, again in my opinion, only
where there is diligent use of carbon dioxide injection systems (with a pH
controller and solenoid valve) is its use warranted. Unfortunately, most
hobbyists use the dump and pray method. Yet, use it correctly and it's an
excellent product!
It only takes about an hour
for the undissolved powder to settle out. No matter the clarity of the upper
fluid, it can then be used. Use the upper water without stirring within a few
days. Then clean out the mixing container and start over. Testing the pH of the
solution is not needed, nor recommended, as it is dangerous because of its high
pH, which is 12. Of course the mixing container should remain closed during
this time because carbon dioxide from the surrounding air will get into the
container, reduce its pH, and precipitate some of its calcium, which you can no
longer dissolve. Simply use up the available solution within a few days and start
over.
If you want to stay with the use of Kalkwasser it
can be purchased at a grocery store as "Pickling Lime." The
difference between Kalkwasser products and Pickling Lime is simply its price
and the amount of impurities each contains. Since Pickling Lime is for human
consumption its impurities have never been a problem in any aquarium that I
know of. I would recommend staying with the one of the two-part solution
calcium/buffer products if you can't afford a calcium reactor.
Hope this helps,
Bob
Dear Mr.
Goemans,
I enjoy your
Sand-Mail column in FAMA and it's the only one I'm guaranteed to read each
month. I have a few questions for you but first I'll give you some info on my
system. I have a 120 gallon main tank with a 75 gallon sump. In the main tank I
have a couple of inches of small aragonite sand with lots of live rock and
corals. No green algae, but lots of coralline. Two 175W 10K MH with two VHO
Actinic. There are also eight powerheads with two returns. I also have an 8
watt UV sterilizer.
On one side of
the sump I have set up a refugium lit with two 8 watt PC. On the other side I'm
trying to establish a propagation area with two 55 watt PC's. Since I put this
system in I haven't used my protein skimmer (two months). I use a Calcium
Reactor to maintain the Calcium and Alkalinity and I dose Strontium and Iodine.
I should mention that I have had 2 different cases (one in summer of 2001 and
the other about a year before that) where the Calcium went sky high (650+)
before I realized what was going on. It ended up killing some frogspawn,
torches, brains, etc.
Now the
questions, easy ones first.
#1. I read in
your January 2002 article that UV Sterilizers kill some wanted items. I read
somewhere about UV's in FAMA and got the impression that I should upgrade to a
much larger size. So now I'm unclear about whether I should have one at all or
if I should run it just occasionally. If I do need one should I get a larger
one. If so, what size and how do I know who makes the best one? Does anybody
test them like they do woodworking tools?
#2. How often,
if ever, should I clean the gravel in my main tank?
#3. Is there a
definitive answer on the small starfish that I see in my tank? Some people say
to remove them, others say they don't do any harm.
#4. Polyp
extension. Some of my corals don't seem to extend their polyps as well as the
ones in my brothers tank (Same setups and same water quality. But different
lighting. He uses four VHO's and two 55 watt PCs. He is still using a skimmer
and he does have outbreaks of algae sometimes - I never do). Some examples- my
Christmas Tree rock worms won't come out during the day, but do at night. His
come out all day. I took a Xenia from his tank that was doing great and put it
in my tank. After 3 days it had never opened up (it was on the bottom). When I
took it back to him, it opened up the next day. His brain corals seem to always
have their tentacles out, where mine never do during the day. I have a plating
Montipora that has grown to over a foot, when I chipped a piece off and put it
in my propagation area, the polyps came out where I could see individual polyps.
I then put my Christmas Tree Rock in the same area and the worms came out almost
immediately.
My first guess
to my extension problem is lighting. My main tank is in a wall, so I'm able to
adjust the height of my lights. They are now about 10" above (previously
about 6-7") the tank. Should I have a protective sheet between the lights
and tank? I never put one on because they were so high I wasn't worried about splash. My second
guess-is it possible that I have something wrong with my water quality that I'm
not testing for? Or not feeding enough? Over all I would say that I've been
successful in my 5 years of having reef tank. I had a red open brain split in
half. A Trumpet go from 8-10 heads to over 60. A Blastomussa that I was able to
catch a 'bud' off and put in my sump where it has turned into two new ones. But
it is frustrating to not be able to have Xenia or a Christmas Tree Rock or see the
polyp extension that others have. Any
help would be appreciated.
Thanks,
Greg Dudley
Hi Greg,
Thanks for your email and good questions. As for UV
sterilizers, and/or the application of ozone, I see them both as good devices
should fishes in a complex reef system develop Amyloodinium or Cryptocaryon.
Otherwise, their use does destroy entities such as floating microalgae,
bacteria, viruses, etc as mentioned in that article. And, some of that can be
used as food for corals. An adequately sized UV or ozone generating equipment
in reserve is like owning car insurance, nice to have and hope you never have
to use it! And if it were my UV for that size aquarium, I would increase its
capacity. Yet, only use it if the need arises.
Some UV manufacturers
recommended a minimum flow rate of about 25 gallons per hour per watt. They
also recommended that the volume of the entire aquarium flow through the
sterilizer once every hour. Therefore a 4 watt unit may provide protection for
a 100 gallon aquarium by operating for one hour. 'May' is the key word! My
recommendation would be that at a minimum a 15 watt unit for a 100 gallon
aquarium be used at the same flow rate. This provides a sure kill ratio since
proper maintenance of these units and/or correct flow rates are rarely
achieved. As for brands, there are many and I'm not familiar with all the current
brands or if anyone can relate to one brand being better than another. I would
stay with a well-known brand name.
As for vacuuming the
substrate, any type sandbed should receive a general cleaning once a month.
I've often heard the comment sandbeds should never be cleaned. If possible I
ask those people if they never dust their home! Anyway, cleaning depends upon
bioload, and generally most detritus is generated from fish waste. You don't
mention how many or size of the fishes in your system, but presume there are
some. Therefore, at a minimum I would recommend vacuuming the accessible sand
areas, reaching down into the full depth of the sand, once a month. In-between
that cleaning I would stir the sand with a chop stick or something similar as
the stirred detritus makes a very good food supply for various polyped animals
and/or tube worms. The stirring also prevents deeper sand areas from performing
the ammonification denitrification process found in areas where oxygen is
depleted, such as in areas below about an inch deep.
The small starfish you name
are probably Asterina anomala, which are usually less than three-quarter
inch and having up to seven legs. They have apparently come from Fiji on live
rock. They appear to be sps, soft coral and coralline eaters. These tan
dime-sized or smaller, yet large bodied starfish are sometimes visible at where
the substrate meets the aquarium side panels when the aquarium lights dim. They
also hide by day under corals. They divide themselves across the main body
producing stars with half a body with two to three legs of various lengths. A
long pair of stainless steel tweezers is a good tool for their removal. A
natural predator would be the harlequin shrimp Hymenocera picta. I take
them out 'every' time I see one!
As for polyp extension,
that's a more difficult situation to resolve. Let's first look at the Christmas
Tree rock worms. I keep my Christmas Tree worm rock about ten inches from a
250W 10K MH lamp and about ten inches from the outflow from a system return
pump, which flows at about 700 gallons per hour. Thus their symbiotic
relationship with the live Porites coral coating the rock is maintained.
It is thought the worms derive nutrition from the coral mucus and in my
aquarium these worms are always out where they are constantly being moved by
the strong water flow. If the Porites dies, so do the worms sooner or
later. Your situation could possibly be lack of water movement/light intensity,
and/or the lack of Porites to supply their diet needs. Opening at night
could be an indication they are looking for plankton that may rise during the
night to supplement their diet needs, or something during the daylight hours is
picking on them.
Xenia is sensitive to nitrate
levels over 5 ppm and may deteriorate if nitrate level exceeds 10 ppm. It is
also sensitive to oxygen levels. Your brother uses a skimmer that oxygenates
the water (you apparently don't use a
skimmer and I can't fathom why anyone would not want to use a skimmer!), and
pulsating may be related to ridding excess oxygen, which can be highly toxic to
the animal. Placing a pulsating Xenia in a tank at the bottom of a tank
where dissolved oxygen was not as high as in the previous tank could be a
reason why it decided not to pulsate. Just a thought, but you may want to check
it out by restarting your skimmer.
As for tentacles being out
on some animals, that's usually a sign they are hungry which is the reason they
have tentacles. They have other means of protecting themselves, but tentacles
are feeding mechanisms. Depending upon the food present or feeding regiment,
their tentacle display is related. Checkout the feeding routines and what is
used, when and how much, and then compare notes.
When it comes to the
distance the lamps are from the surface of the water, there are only two
considerations in my opinion and they are the heat generated and splash/safety.
If they are in a hood with a splashguard and the aquarium has a chiller or
their heat is not a problem, then I want my lights as close to the surface as
feasible. We need to realize the further away the source of light, the less
light reaches the target organisms. If your lamps are not shielded, I suggest
doing so and moving them closer to the water surface. But that doesn't mean
installing a cover over the entire aquarium as that would interfere with good
gas exchange.
A refugium on some
installations helps with maintaining a more natural pH and alkalinity level,
especially when lit at an opposite timeframe than the main system. Since your
main aquarium sandbed is shallow and directly on the aquarium bottom, a
refugium is a good addition. Also, with the refugium's light source close to
photosynthetic frags, it makes for a good propagation area.
All in all it sounds like
you are having good success with your system. Could be some minor changes as
recommended above might provide the improvement you're looking for. Hope this
helps and keep me posted.
Bob
Hi Bob,
I read your
column in FAMA and I have a question concerning heaters. I previously
maintained a 10 gallon micro reef for about 3 years and I'm now upgrading to a
75 gallon reef with a sump and skimmer. My question pertains to heater wattage.
I have numerous books and have seen recommendations as low as 2 watts per
gallon and as high as 8 watts per gallon. I'd like to install 2 heaters in the
sump, each running off a different surge protector. The sump will probably hold
10 - 20 gallons when running. None of the recommendations indicate if that is
for total water capacity or actual water volume which will differ greatly once
the rock and sand is in. I know both too high or too low wattage will both be
ineffective. I'm thinking about using two 150 watt heaters. Do you have any
thoughts or recommendations on this?
Thanks,
Jeff
Hi Jeff,
For heater sizes my
rule-of-thumb is 2 to 4 watts "per total gallons in the system." Keep
in mind should a heater malfunction it will take longer to overheat an aquarium
with a lower wattage heater than one of higher wattage. Even in colder areas
where a higher wattage heater would prevent large swings in temperature I would
recommend using two or more smaller wattage heaters than a single high wattage
heater so as to prevent a possible fried fish situation.
Placement should be in an
area where there is sufficient water movement. Insufficient water movement past
the heater can cause a high heat area near the heater possibly stressing any
animal that comes too close. Sump areas where there are no snails and other
slow moving animals are an excellent place. When installing a new heater allow
for the unit's internal temperature to match the temperature of the aquarium
water before plugging it in and setting the temperature. This may take about an
hour. Stay with name-brands.
Hope this helps,
Bob
Hi Bob:
I wish to
commend you on a Sand-Mail response in a past issue of FAMA. You cleared up
many questions that I have been pondering. I used to work for an Aquarium store
and also took on some maintenance clients as well (the store offered no such
service at the time). What you pinpointed was the fact that many snails and
hermits can have an adverse affect on algae. My theory is that they are merely
weed eaters not weed killers. If introduced into a system with no or little
algae and quality live rock they will do a good job in maintaining its beauty.
However as you stated they won't solve the problem and overstocking of such
critters can lead to more nutrients as they die without notice. In my
experience in tackling systems with excessive algae growth it is to scrub the
rock. Out of the tank is preferred, yet in tank with a siphon works well also.
What I found works great is using a toothbrush attached to the end of a diatom
filter. It can be hard work, but is well worth it.
My question is;
have you seen any correlation between cyanobacteria and low temperatures?
Previously I owned a 55 and 30 gallon live rock fish-only tanks before I moved
to Japan. The 55 had a plenum and the 30 just straight sand. Each had 1.5 lb.
of quality Fiji live rock per gallon that was properly cured by the distributor
and then I placed the rock in a holding tub with a skimmer, herbivores, and actinic
lighting for a week to avoid placing any excess die off in the tank. It was
then rinsed using saltwater through a powerhead.
Here I have 20
gallon setup like the 30 gallon. They all have adequate skimming and water
changes are performed as well as proper maintenance. Let me say the lighting is
not where it should be, with only 3 watts a gallon. I used my aquariums to test
on so I could better understand problems in others. I ran all of them without a
heater for a while and noticed that cyanobacteria began to form when the temp
fell below 75 degrees Fahrenheit. I never let it get below 70 because of the
fish, which was a low load. After placing heaters in the tanks and slowly raising the temp to 78 I found that the
cyanobacteria began to dissipate. No other changes were made during the heating
test. Have you seen this before or was it pure coincidence? Rarely do or should
any aquariums fall below 74 degrees, but I was puzzled when this occurred. I
have read and experienced algae blooms with temps above 80. While diving I have
also seen that hair algae and blue green algae occur in shallower depths and
warmer waters. I know many factors
effect algae so I want to study all of them to better care for the precious
life that encompasses our hobby. If you
have any input or know of any articles that show and prove relations between temperature
and algae it would be helpful.
Thanks,
Joseph Cortez
Okinawa, Japan
Hi Joseph,
Thanks for your email and
interesting questions. Temperature is not of any significance when it comes to
the proliferation of cyanobacteria in the noted range. Nor is temperature, in
my opinion, the primary cause of coral bleaching! However, in both
circumstances the quality of light seen by the organism is of significance.
Cyanobacteria are enhanced with red waveband light. Corals are not. When surrounding
water quality changes, which includes density changes and/or skewing with
improper use of additives, light refraction may be affected. Change the shorter
blue waveband lengths to longer red
waveband lengths and corals suffer, yet cyanobacteria benefit.
In your example the lower
70 degree water may have slowed metabolism in many of the aquariums creatures
thereby resulting in a more nutrient rich environment, which in turn benefited
cyanobacteria. As temperature increased to more normal levels for these
creatures, their metabolism increased and better used the food supply.
Surrounding waters then became somewhat less nutrient rich and cyanobacteria
levels dwindled.
Bob
Dear Bob,
Read with great
interest a letter to your Sand Mail column in FAMA on the subject of using
natural sunlight to light a reef aquarium. I must admit that I was a little
disappointed by your reply, as I was hoping for some more specific information.
You see I am in the process of building a 2500 liter tank from plywood and
fiberglass, which I intend to be a reef. This tank is in it's own concrete
floored annex to the house, with only the front glass visible in the house, and
above it I have made a 2.4 by 1.2 meter skylight from a two-skinned product
called Thermoclear which the retailers assured me will pass 80% of the light.
This skylight is about 1.5 meters above
the water level, (water will be about 750 millimeters deep) and I will line the
walls of the room with silver foil to increase reflectivity. I will also use
six 150 watt metal halide lamps for the later part of the day and the evening.
I can't at this stage afford to run (or buy) stronger lights than these, and I
feel that I will get a great deal of blue light through the skylight (after all
the sky is blue) so don't plan to use actinics. I expect some loss of heat on
cold nights and some heating problems in summer, but can use lots of
ventilation to deal with that. I plan to heat the room rather than the tank to
reduce evaporation and condensation). I live in Auckland New Zealand and our
light is very bright and intense and strongly ultraviolet. Using this set-up I
will also get considerable variation, clouds, dull days, very bright days,
etc.
I saw in the
Delbeek and Sprung Vol. 2 the pictures of the tanks at the Waikiki Aquarium
using a mixture of natural light and halides but their web-site had no
information on this subject at all. I have also followed the debate on using
live sand either with a plenum or on the tank floor; alas all rather academic
in New Zealand as neither live sand or live rock are available here owing to
our very strict laws on imports of possibly environmentally dangerous
organisms. Due to our small population and consequently small number of reef
hobbyists it doesn't seem possible to bring enough pressure to change this, and
with the Pacific Islands not far to the north it is very frustrating! We can
get dead coral rock and sand, also a good variety of soft and hard corals, also
fishes, so all is not lost!
I am planning
on using only several large home-made protein skimmers to filter my tank. As I
live fairly near the sea, natural water, and water changes are no problem.
However, I would appreciate some advice on setting up a "live sand"
bed or it's equivalent when one can't get real live
sand. All the
sites I've found on the net assume the availability of live rock and sand.
Thank you,
Brian Timms
Auckland, New
Zealand.
Hi Brian,
Let me first say that I've
always wanted to visit New Zealand as I've seen many articles and photographs
on its beauty and wonderful people. It sounds like a place I might never want
to leave!
As for your email, I recommend
requesting a chart showing what wavelength light passes through the product
mentioned. If everything in the blue range and below is filtered out, and only
the wavelengths such as yellow and red are allowed through, that does not
benefit a reef system, no matter how bright it is. If light of 385 nanometers
and above does pass through the product, then there may be sufficient blue
spectrum to adequately trigger photosynthesis. And blue is the wavelength of
choice when it comes to corals.
Yes, there is quite a lot
of debate when it comes to sandbeds. Controversy is good for any subject, but
needs to be voiced it in a professional and responsible fashion. After six
years of researching sandbed microbial processes, a lot has been learned. One
of those things has been the identification of microbial processes in sandbeds
of different grain size and depth. Those findings have lent themselves to
understanding system balance. This is of course, crucial to long-term success.
Anyone can put together general system components such as sand, rock, pumps,
and lighting and have something looking great for the short term. However, in
my opinion, it's long-term success of the system that is all-important.
Those that understand and
take into consideration the true foundation makers of a closed system, the
microbial processes, are those that have more success. Simply fact, not
fiction!
One of the more important
findings centered on sandbed oxygen content. Where small amounts of oxygen
existed, such as 0.5 to 2.0 mg/l, or what should be called the anoxic zone,
bacteria reduced nitrate back to gaseous elemental forms. This is termed
dissimilatory denitrification. Another plus in this area was that these
bacteria were more than 30 times more efficient than those found in zones where
there was less oxygen. This resulted in much better use of phosphorous and far
less production of phosphate!
Unfortunately those that
stress deep sandbed usage directly on the aquarium bottom are still clinging to
the belief that their beloved method is superior to the Jaubert plenum method.
They have expressed numerous conditions that range from plausible to
ridiculous. Yet, fact is that when oxygen content is below the anoxic level,
bacteria operating in that zone reduce nitrate back to ammonia/ammonium, no
further. It is called the ammonification process or assimilatory
denitrification (reassembly of ammonium, i.e., ammonification). Not only is
another nitrogen product produced, the bacteria's inefficient use of
phosphorous for energy results in an abundant amount of phosphate being leached
into the surroundings. So in essence, deep sandbeds are more a never-ending
circle/cycle of oxidizing the same nutrients over and over again! Unfortunately
this mass of oxidation becomes greater with the age of the system. How long
will it take for parts of that 'mass' to leach into the bulk water is anyone's guess.
Of course, the influx of benthic invertebrate helps bring in additional oxygen in
some areas and can help lessen the impact to water quality and system balance.
But I would not want to hang my hat so to speak on that there will be
sufficient influx and the right type invertebrate! I would prefer a method where oxidized nitrogen products in their
elemental form are expeditiously returned to the bulk water.
As for using live sand, it
is much more sensible to begin a system with live than dead/inert sand. Having
a new system with more usable bacteria than nutrients gives the system a better
chance for the microbes to become established before unwanted forms of algae!
If the number of microbes are there, they can use whatever nutrients the new
system has for growth and reproduction. If they are not there, those nutrients
will lead to algae becoming established. So, if carbonate-like sand is
available in any near-by shore areas, use it. If not, first establish a bed in
the aquarium with no rock or animals. Use one of the many starting additives
that help initiate the nitrification cycle. When that completes, then add the rest
of the decor.
I hope this is helpful,
Bob