By Bob Goemans
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Bob Goemans corresponds with Shelly Morrell (Ocala, FL)

Shelly Morrell (Ocala, FL) writes...

Dear Bob,

I write to you, hoping you can shed some light on my problem. Three months ago I had a red slime break out so I used a medication to remove it (which I have used 3 other times prior to that). I did a water change 24 hrs after introducing the medication into the tank. From there on all went down hill. Within days ALL fish had died. The rest of my clams and corals looked "not happy" - Oh, I am getting ahead of myself. I have a 75 gallon reef tank and it has a wet/dry with VHO lighting and a protein skimmer. All equipment appears to be working fine, and I also checked the electric current in the water (just in case). Ok back to the downfall. Fish dead, corals and clam not happy. I began doing 20% water changes every few days, still no luck. While I continued water changes, I waited about 2 weeks to add a damselfish back in. It died within a few hours, sinking to the bottom laboring for air and then died. Ok, so I ask every fish store owner and I even e-mailed Robert Fenner for his advice, which was to do water changes and add Chemi-pure and Poly Filters and then wait! Ok, I have now waited 3 months and the clams and corals are doing much better. Although I still cannot add fish, as they continue to die within 2 - 3 hours by sinking to the bottom. I have done everything I can think of and what others have mentioned with no luck. Do you have any ideas? The water reading tests have been normal throughout this whole mess, and its not just my testing equipment, as I have had the water tested by 3 different local stores just to be sure all were getting the same readings.

HELP! If you can. The next move is tearing down the tank and starting fresh. Which isn't something I care to do. Let me also say about 2 months back I did a 75% water change as I thought what do I have to lose! Still no luck. I have even checked all my pumps, which are working good, thinking maybe it was an oxygen problem? I am stumped!

Thank you,

Shelly Morrell - Ocala, FL

Bob replies...

Hi Shelly,

Sorry to see this happening, and can understand your frustration. But your letter leaves me with a lot of questions. If you can, please answer them as "completely" as possible;

1) Exactly what water quality tests are you performing, and what are their exact readings. And what brand kits are being used? (Those being tested should include specific gravity, pH, ammonia, nitrite, nitrate, copper, and dissolved oxygen. If they don't then test them (especially the oxygen) and give me the results - they are all important parameters!)

2) Do you use any additives, and if so, what are they?

3) What brand anti red algae products have you used?

4) How deep is the sandbed in your aquarium? What type sand is it - what is its grain size? Do you see any dark areas in the sandbed? Do you ever vacuum/clean the sandbed?

5) Do you use processed water (RO/DI) for evaporation makeup and/or water changes?

6) Is the tank top covered or open to the air?

7) How old is the set up? How many fish did it have? What type inverts have been/are in the tank?

8) What kind of water movement occurs in the tank?

This would all help point the way.


Shelly Morrell (Ocala, FL) writes...

Hi Bob,

I test with "Saltwater Master" - I have not nor does anyone around me test for Oxygen.

ph - has been 8.4

Ammonia - 0

Nitrite - 0 - .5

Nitrate -0

Copper - 0

AragaMILK (CarbiSea), Reef Iodine (Seachem), DT's Phytoplankton

UltraLife Red Slime Remover

Yes, I vacuum the sand bed weekly with my water changes. Its about 3-4 inches deep, and its live sand mixed with crushed coral and believe its been in there 4 yrs.

I use RO water.

The top is enclosed with glass and a light canopy.

Six fish, 3 damsels, 1 Yellow Tang, 1 Clownfish, 1 Basslet - I currently have a medium sized clam, which is doing wonderful, an anemone, 2 gorgonians, and 1 moon polyp.

I have a wet/dry and a protein skimmer for this 75 gallon tank.

Hope this helps you



Bob replies...

Hi Shelly,

Thanks for the answers and they do help. I can understand others saying do water changes, etc., as that helps solve some baffling situations. However, where you're concerned, I see several more areas that I would like improved.

Lets first address your water tests: You forgot to include your specific gravity, which should be about 1.025 - if much lower (1.022 - 1.03), raise it and keep it at this level. As to dissolved oxygen, you're no doubt correct that few people test for it. Nevertheless, from what I've read in your letters, its one angle that should be addressed. Yet, if they were dying from lack of oxygen, they should be hovering near the surface with their mouth forming a square-like shape as they try to suck in as much water with oxygen as possible. Not sink in the water and die at the bottom. But if you find it possible and find an O2 kit, and the level is about 5 ppm, that's far too low. It should be about 6 - 7 ppm!

Furthermore, if the top of the aquarium is covered in glass and the hood, and contains no open areas to the air in the 'room,' then there is improper gas exchange at the surface of the water, which will cause the dissolved oxygen in the aquarium to fall to dangerously low amounts. If you have this condition, remove most of the glass covering and insert a couple of airstones 'under' the trickle section of your wet/dry. That will markedly increase O2 in the aquarium. And would also check the efficiency of your skimmer.

As for other water tests, I doubt your pH is really 8.4, simply because of the lack of gas exchange with a covered aquarium, and suggest checking that with another brand test kit.

A reason for the nitrite level is the fact you vacuum far too often! Once a month will suffice, as more often causes the bacteria to work overtime reestablishing themselves, which leads to the nitrite condition you now have.

The next area is the additives: If you have cyanobacteria problems, the reason for them is over feeding, feeding incorrect foodstuffs, poor water movement, incorrect lighting spectrum, and poor general maintenance. The ways to correct it (in your case) is by improving water movement and correcting what is used as foodstuffs. As good as phyto and zooplankton foodstuffs are, they can easily be overused. I recommend at least cutting back on their usage or temporally holding back their use altogether until this problem has past. Also improving water motion in the aquarium. And as for additives used to wipeout cyanobacteria, I highly recommend 'never' using a product that contains an antibiotic. Even though it will/may kill this unwanted pest, it can make the bacteria stronger and more resistant the next time around. It's really much wiser to get to the root of the problem causing this problem, then to put antibiotics into your aquarium. However, where such additives are involved, I only recommend one brand, Boyd's Chemi-Clean, because I understand its chemical makeup and how it works. It's 'not' an antibiotic, and because of its chemistry, causes the bacteria to consume itself. I've seen one simple treatment end all traces of the bacteria without harming anything in the aquarium, fish or inverts. And after resolving the cyano problem, I usually recommend putting one teaspoon of 'brown' sugar or one teaspoon of unprocessed honey in a 100 gallon tank once per month after that to end future cyano problems.

As for iodine usage, I prefer not to use it or at least in far less amounts than what most brands recommend, as today's test kits are too accurate.

Furthermore, suggest installing a couple of small powerheads to stir the water's surface. And as a 'catch-all' install another 'new' Poly-Filter somewhere in the system where water can flow through it.

Try another small fish in a week, and let me know how it goes.


Note, a week later Shelly noted that a fish was added, seemed ok for 5 hours this time, but died after 8 hours. Again sinking to the bottom.

Hi Shelly,

I've saved all your letters (about 10) and have reread them. Problems in aquaria fascinate me, and I don't give up easily!

Here's another road to go, as I'm questioning the accuracy of test kits with liquid reagents, as those reagents are often too old or mismanaged to render accurate readings, so I wonder about your initial ammonia reading in your first letter. If you had up to 0.5 ppm of nitrite (or more), it meant that there was a considerable amount of ammonia in the aquarium prior to that. And you said it was zero. If I'm correct, that came from two things, the over cleaning of the bottom sand (we already discussed that) and the use of the chemicals to kill off the cyanobacteria (we also discussed that). This can open the door to two problem areas, Toxic Tank Syndrome (TTS), or New Tank Syndrome (NTS).

By introducing this chemical, it could have caused the gram-positive bacteria (both in your sandbed and the cyano) to die-off. In turn it could have resulted in two conditions - the entire bacteria in the aquarium having to reestablish themselves (NTS), and/or created a toxin that will 'not' be pulled out by a Poly-Filter (TTS). If it's the toxin, then starting over is the only way to go. However, if things continue to improve, that's a good sign. To increase the viability of the good bacteria in the aquarium, 'PLEASE" do the following - order a package of Fritzyme #9 in the 'concentrated' form. Go on the web to search it out. Use as directed and after about four days, try another fish. Let me know what happens. It will quickly reestablish your 'good' bacteria.

If that doesn't happen, then I think you have a case of ammonia/nitrite poisoning and the toxins produced (TTS) cannot be corrected. If so, then the entire aquarium needs to be drained and disinfected with bleach, and restarted. Hope it doesn't go this road.


Shelly Morrell (Ocala, FL) writes...

Hi Bob,

Again thank you so much and I will e-mail you after I try this. By the way, I should mention that I got your email address from the one of my favorite fish stores in town, and he really speaks very highly of you.


Shelly Morrell (Ocala, FL) writes...

Hello Bob,

Fortunately there was a shop near me that carried the Fritzyme #9 in the 'concentrated' form. It's now going on the 3rd week after I put that in and wanted to let you know all is good in the tank. I added some fish a week later, and they are all dong great! My polyps, clams, and anemones are also going wonderful. Again, thank you for all your advice. I have learned so much during these past few months.


Bob replies...

Hi Shelly,

I'm so happy to see this, and it makes me feel good way down inside me. May you have many years of success!



Unexpected Mortalities; New Tank Syndrome

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