By Bob Goemans
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Bob Goemans corresponds with Michael Henson (Gerrardstown, West Virginia)

Michael Henson (Gerrardstown, West Virginia) writes...

Hi Bob,

I have been in the trade for 20+ years and have never been so frustrated as I am now! I have a 370-gallon reef tank, which is about three months old. My problem began with cyanobacteria, but I resolved that by siphoning and vacuuming the sand and doing some major water changes. Then it turned to dinoflagellates for a short time, then that went away on its own after a week or two. Then began my present problem when an ugly brown hair alga began to take over all my live rock. I proceeded to take out all the live rock and scrub it with a toothbrush and then placed it back in the aquarium. I also did some big water changes. But it seems to be coming back, and wonder why I've had these problems and what to do further to get things back to normal.

Here is some info about my aquarium;


1 Imperator Angel 4-5 inches

1 Sailfin Tang 4-5 inches

1 Purple Tang 3-4 inches

1 Yellow Tang 2-3 inches

1 Percula Clownfish

1 Freckeled Hawkfish

2 Domino Damselfish

4 Green Chromis

25 Scarlet Hermits

10 Turbo Snails

100 Red Leg Hermits

25 Blue Leg Hermits

70 Nasurius Snails

1 Elegance Coral

2 Star Polyps

2 Mushroom Rocks

1 Bubbletip Anemone

1 Giant Cup Mushroom

1 Colt Coral

1 Staghorn sps

3 Purple Montipora sps

2 Green Montipora

2 Tabletop sps

3 Zoanthid Rocks

4 Leather Corals

1 Crocea 4-5 inches

1 Derasa 2-3 inches

(Clams are growing nicely as they have approximately ΒΌ" of new growth)


I use an HSA 1000 protein skimmer. But not sure it running correctly, but did call MTC, but still not sure. You had a review of this skimmer on your website, so can you give me any further info on it? The skimmer has an 1100-gallon an hour Blueline pressure pump on it.

Lighting is new, two 400 watt 20,000K, two 250 watt 10,000K, and three 96 watt actinics - all on timers for 11 hours with sun up to sun down photoperiod.

450 lb live rock (half of the rock was transferred from a 110 gallon tank that was doing ok)

160 lb live reef sand by CaribSea

I have 1600 gallons flowing in the tank with 2200 gallons flowing through sump back to tank.

I use 7 inch filter socks and three are changed every other day.

My RO unit is a SpectraPure RO/DI Max and has the silica buster cartridge at the end.

I was using a Kalkwasser reactor, but it seemed to make the cyanobacteria worse at the time, so I stopped using it.

I use a calcium reactor, which keeps my alkalinity at about 11 dKH with my calcium staying at 440 ppm.

I have a 40-gallon refugium and a 40-gallon frag tank with its frags growing well, and both are attached to the main system.

I have a 90 gallon tank hooked up with RO/DI water to auto top off the sump.

Water Chemistry

I do use several good test kits, Salifert, LaMotte, and Merck, all distributed by Deltec.

Nitrate 2.0 ppm

Ammonia 0

Nitrite 0

Phosphate with 3 test kits about 0.008 ppm

Silicate below 0.08 ppm

pH of the tank stays at 8.26 during the day and at night only drops to 8.05 due to the frag tank and the refugium lights on at an opposite light cycle than the main tank. I also have amphipods and the like all throughout the refugium and see some in the main tank from time to time.

I also do 35-gallon water changes every 2 weeks - roughly 25% a month. I use my RO unit to make the water for water changes, and let it mix for 24 hours before using it.

As for feeding my fish, I only feed them every other day, and only frozen mysis shrimp and Cyclop-eeze.

I would appreciate any input you could give me as to what could be causing the algae blooms


Michael Henson

Gerrardstown, West Virginia

Bob replies...

Hi Mike,

Thanks for your well-written letter, and the complaints about unwanted alga of some sort seem to be an endless subject matter where my email is concerned! And from what I can see in your letter, you have had a settling-in sort of experience where some unwanted situations arise while aquarium microbial processes are establishing their relationships/balance with other classes of bacterium in the aquarium, or what can be referred to as 'equilibrium.' This overall set of processes can take about six months to get fully established in a well-managed system. If not well managed, it may never become properly established. But you seem to have excellent equipment, test kits, and the systems water quality also appears to be very good.

So what I can gather from your well-written letter, - the cyano problem probably began in some nutrient rich areas, possibly having some excess ammonium/phosphate, which got small patches of it going. And the reason the cyano seemed to expand more when Kalkwasser was used is because the very high pH of Kalkwasser was precipitating some phosphate as calcium phosphate, which covered some surface areas in the aquarium. And anywhere the cyano covered some of the precipitated phosphate, it reduced/oxidized the precipitant, thereby gaining its phosphate for growth. Of course, this will not generally happen elsewhere in the aquarium, as the compound remains stable unless a microbial slime/algae growth encompasses it. So when you stopped Kalkwasser use 'and' removed the slime by siphoning/vacuuming, you eliminated these fertile areas and gave the system some more time to adjust/balance itself microbial-wise.

As for the dinoflagellate situation, this free-swimming form of brown algae probably came in on some new coral added to the tank and found some organic rich areas to help expand its growth. But your attention to what it takes to maintain better water quality and not overfeeding your livestock, caused it to dissipate on its own.

Where brown alga is concerned, there's also good news there. I believe it got it got its start, as did the cyano. And because it now has a mat-like base, is capable of prolonging its growth by making its own nutrients under its base, where anaerobic conditions exist. And the only way to eliminate it is with a lot of handwork, as the areas having this growth need to be hand-cleaned/removed. And as you do, I would expect new growth of this alga to diminish and within a few months, be almost nonexistent.

Nevertheless, when cleaned, some short growths will reappear, and this is where your ample supply of hermits will be able to help, as they can only feed upon short growths, not the long-like hair growths when the algae becomes more established. But remember, hermit and snail poop need to be vacuumed monthly, as excessive amounts on/in the sandbed will only add unwanted nutrients to the bulk water.

Another thought to keep in mind, is the choice of media in the calcium reactor. A poor choice here can add unwanted silica and phosphate. Even though they may not register on your test kits, it could be just enough to initiate an unwanted algae situation. The only two choices in reactor media in my opinion are; CaribSea ARM, and the German KORALlith media.

As for that Marine Technical Concepts skimmer review, that was a long time ago! But do recall a situation with the one piece beckett valve in the top of the High Speed Aeration (HSA) unit. I highly recommended to the owners of the company that the enclosed one piece beckett be changed to a two piece beckett that simply was two vertical half's that snapped together and it be placed in a similar chamber, but one that opens so the beckett could be removed and easily cleaned. After a lot of experience with this unit, which was probably one of the best skimmers I ever had, I found salt creep quickly occurring in the beckett, which was difficult at best to clean since only 'its' intake opening was accessible to push a tiny pipe brush or pipe cleaner through. And because of its center bulbous fitting, could not see if it were totally cleaned out. So a lot of guesswork and frustration went into keeping it clean, but when clean, it worked with exceptionable efficiency. Therefore, I recommend shutting the skimmer down and removing the top chamber and cleaning that beckett as best you can, as cleanliness of that beckett valve may be your problem with getting good skimming results. Check it out.

And where feeding is concerned, I always grimace when someone says 'they only feed every other day.' Just keep in mind underfeeding is just as bad as overfeeding! Checkout my new Microcosm book titled "Marine Fish Health & Feeding Handbook," as there's much info on proper feeding along with the various maladies that can affect out fish. Also, a new medication is discussed that is appearing to quickly and very effectively treat parasitic infestations such as the common Marine Ich (Cryptocaryon irritans), Marine Velvet (Amyloodinium ocellatum), and Clownfish disease (Brooklynella hostilis), whether the fish are in a fish-only or reef aquarium. And it's expected to be also very successful in freshwater aquariums!

From what I can see, after being up and running for three months, I think you're nearing the end of some unwanted situations. And because of your excellent equipment and experience in the hobby, your aquarium future looks very good. So stay after the brown alga as I expect it too will soon diminish.

I hope the above helps,



Algae Control

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