Why won't the Nitrite in my marine aquarium go down?

Question

I've had my tank for more than a month and it cycled completely before I added any fish. I originally had issues with ammonia because I added too much food to get the cycle going. Now, the ammonia has shown at 0 ppm and I test it daily. It's been that way for 2 weeks now. My nitrites spiked then returned to 0 as well. However, for about the past week nitrites have been spiking again > 1 ppm. Ammonia is still at 0 ppm, and Nitrates steadily climb. I've done 25% water changes to keep my fish healthy, but nitrites still increase way too quickly. What can I do? I tested the tank today and here are the specs: Ammonia 0 ppm; Nitrite 1.5 ppm; Nitrate 40 ppm. I've used Hagen Cycle to aid in the cycling.

I forgot to say that I have about 20 lbs of live sand in there too.

I only feed 2 times a week, especially since I noticed this problem. My clown is begging ;)

Answer 1

Don't do so many water changes. This cycle happens from fish shock and too many water changes, but it is also a normal happening. Temporarely, they will go up, then down. It is a long process, but it is nothing to worry about. Just keep an eye on your fish, and don't add any more, or any at all until they are all steady.

-hope this helped.

Answer 2

First, you need a partial water change because the nitrite is higher than your fish should be in and the nitrate is borderline.

When you cycle, there are two sets of bacteria involved. The first converts the ammonia to nitrite, and these seem to be doing a good job since the ammonia = 0. A different set convert the nitrite to nitrate. These tend to lag behind the ammonia converters since they have to wait for the nitrite to be produced. You may just not have a sufficient population to convert the all the nitrite to nitrate yet. BTW, your tank ISN'T completely cycled - that doesn't happen until the only water test producing readable results is the nitrate. This usually takes 6 weeks, so if you've got fish in the tank, they may be subject to nitrite poisoning. It/they are the new ammonia source, and although the added ammonia is being converted to nitrite, all the nitrite isn't being converted to nitrate - yet!

So your clown might not just be begging for food, if he's at the top of the tank gasping at the water surface, this is an indication of too much nitrites in the water.

Answer 3

I am not a fish nutritionist, but I would guess that you are still overfeeding protein, and the aeration is converting ammonia to nitrite and then on into nitrate. You might try adding additional plants of some kind to utilize the nitrogen components. Active growth from the plants should do this.
Some forms of algae will also utilize and lower the nitrogen compounds.

Answer 4

Main reasons for high nitrites are overfeeding and/or too many fish in the tank.

To lower it you can buy nitrizorb, or you can add a little extra aquarium salt. I would suggest a partial water change, but if you've already done that, you wont need to do it again for a few weeks.