ammonia and nitrite levels aren't zero.

[Kenneth Paul]

I set my first reef tank up 6 months ago. For the most part everything has gone great, but I have have been having traces of ammonia(usually 0.12) since shortly after introducing my first fish. I do find it difficult to guestimate the results as yellow is 0 ammonia and olive green is 0.25. My results are never the bright yellow as on the card, but usually yellow with just a slight hint of green in there. My nitrite is also usually around 0.1. Other measurement are PH-8.3, nitrate 5, Alkalinity 3.0, calcium 400, and no measurable phosphate. I have a 75 gallon tank with 95lbs of live rock. Lighting is 4 VHO bulbs for 440 watts. I use a little giant in line pump which pumps around 400 gallons of water per hour and use 1 powerhead that pumps 290 gallons an hour. Livestock presently includes 5 green chromis, 1 foxface rabbitfish, 2 blue regal tangs, 1 goldenhead sleeper goby, 1 red lyretail hawkfish, 1 sebae clown, 1 sandsifter star, 1 blue linkia star and a serpent star. I also have various hard, soft and leather corals. I do have a sump with an aquaclear skimmer that is rated for a 150 gallon aquarium. I depend on my live rock for my biological filter. My figi rock was not fully cured when I received it so I did cure it for 1 month prior to introducing any fish at which point I believed all die off had stopped. I do use a turkey baster to blow detritus from the rocks as I seem to get a good bit of this and wonder if this is the cause of the ammonia. My corraline alga growth is pretty good and my fish do not appear stressed. I do a 10 percent water change every 2 weeks. I have tried a second test kit to verify what the red sea test is telling me.

 

[pez]

A properly functioning tank will have undetectable levels of nitrite and ammonia (using hobbyist kits). Sounds like to me you have bad test kits. You might want to get a second opinion first, before you take any action.

Is it possible something has died in the tank without you knowing about it? Thus causing excess ammonia? Also, have you used any antibiotics? They generally have a delirious effect on nitrifying bacteria.

If the corals and fish seem happy, I wouldn't sweat it.

-Tom

 

[SAT]

I agree with pez that you should double check your tests. If they're bad, you can ignore the rest of this post. Assuming you have done that, however, you should take steps to reduce your waste levels.

Ammonia and nitrite are generally considered easy to control, at least compared to other wastes. A "normal" level would be undetectable by any hobbyist test kit. Having measurable levels indicates your load exceeds your ability to process those wastes.

You do have quite a few fish and your only mechanism for processing nitrogen wastes is the live rock. The skimmer helps, but much nitrogen waste is never in a form that a skimmer can remove. The capacity of live rock is impossible to predict and is certainly not unlimited. You may simply have too many fish or too little biological filtering capacity for this tank. It's also possible that you have something fouling the water or, as pez suggested, you have done something to damange the biological filtration. Also test your make-up water to make sure it's clean.

As a short term measure, I recommend cutting the number of fish in half. Once the levels stabilize at zero, you can start putting them back in. You should never even think about adding a new animal if ammonia or nitrite are detectable.

You might also consider boosting your biological filtering capacity. Any fine-grain sand bed, but preferably a properly set up DSB, will increase your carrying capacity considerably. Even using an old fashioned wet/dry or sponge filter will be better than having detectable ammonia in the water (you might end up with a nitrate problem, but that's far less toxic).

 

[Kenneth Paul]

Thanks pez and SAT. I think you may be right about the test kit. I didn't think this was the problem as I had tested my tankwater with 2 different ammonia kits. I just tested my makeup water and I'm coming up with the same readings on nitrite and ammonia as my tank water. The makeup water I tested is R/O D/O from my Spectrapure filter. I can't imagine how ammonia could possible be introduced into this water. Thanks again. What's the most reliable testing kit?

 

[SAT]

I prefer LaMotte. They make serious test kits, unlike most kits sold for the hobby.

 

[naesco]

I agree that your problem is likely that you have too many fish in your tank for a 75 gallon setup. You have also added them too quickly IMO.
Your best advice is to try to trade the tangs for some critters, snails etc. If not,if you are having trouble stabilizing the tanks water you will also likely have algae problems coming soon.