I'm confused!

[beenyoung]

Hi Everybody,

Last night I tested the nitrite level in my age tank. It's 0.5ppm! Then I tested the tap water and it's 0. I thought there were some bacteria in my age tank so I sterlized it with PP. After that, I filled it with tap water again. This morning I tested it again and the reading is again 0.5ppm!

Does anybody know what's the problem? :(

Thanks.

Bin

[Alight]

Sterilizing to try to control Nitrites will not work.

Nitrites result when ammonia is converted by nitrifying bacteria to nitrites. Nitrites are futher converted to nitrates if enough nitrifying bacteria of the right type is present.

Ammonia is toxic. Nitrites are even more toxic. Nitrates are only toxic in quite high concentrations (40 ppm or more).

Without knowing much more about your tank, it's impossible to know the source of the nitrites.

The number 1 cause of ammonia and nitrites is an uncycled tank. A tank in which nitrifying bacteria has not been established.

If your tank is truly "aged" meaning all the nitrifying bacteria have been well established (takes at least 3 weeks--many times more), then sources of nitrite could be:

Overfeeding (you fed more than in the past, and excess food and increased fish feces and ammonia waste products have suddenly increased, and your biofilter (the above mentioned bacteria) can't take care of it all.
In this case, simply reduce feeding and your nitrites will return to zero. Or you can continue to feed at this level and eventually (4 days - a week) your bacteria will grow enough to take care of the additional nitrite and it will return to zero.

Dead fish or plants--unnoticed dead things can add suddenly to the ammonia and nitrite load, so that that bacteria can't keep up.

Overloaded-you either increased the number of fish in your tank suddenly, or to have so many fish that there can never be enough bacteria to take care of all of the waste material

medications-some medications will kill nitrifying bacteria. Maroxy is one. Erythromycin is another (Maracyn) and Levamisole is another. I don't know if PP will or not. I think it will if in high enough concentrations.

Cleaning filter media in chlorinated water, or replacing filter media--most of the nitrifying bacteria is found in your filter. Never replace all of your filter media at the same time. Also never rinse or clean your filter media in very hot, or chlorinated tap water.

Sudden removal of large numbers of live plants--plants absorb ammonia, and nitrates. Your nitrifying bacteria adjust to the amount of ammonia they get each day. If plants are removed, the amount of ammonia that the bacteria have to change to nitrates is suddenly increased, and they can't use it all, so ammonia and nitrites result. Eventually, they will multiply to take care of the new load. To prevent ammonia and nitrite spikes, if you are removing plants, do it gradually.

These are the most common causes, and have been reported in threads again and again at various aquarium sites.

In any case, ammonia and nitrites can and should be reduced by making large daily water changes--70-80% if nitrites are 0.5, until nitrites are reading zero (no traces of it). Then, reduce your water changes to 50% at day or so. Enough to keep your nitrates (not nitrites) at least under 10 ppm and hopefully under 5 ppm.

[beenyoung]

Thank you for the reply.

I'm sorry I didn't make it clear. It is the tank for water storage. I never kept fish in it. I just pumped out all the water and fill it again. One hour passed. The reading of nitrite is still 0. I'm not sure if the carbon cause the problem because I took out carbon this time. Is it possible that some bacteria stuck on carbon.

[Alight]

OK, that makes it easier!

Water, unless it is distilled, always has some organic contaminants in it. In tap water, the bacteria, etc. have been killed with chlorine, but the organics that they are made from are still in the water.

Once the water has aged, and the chlorine is gone from the water, bacteria will grow on the organics in the water, and will begin the nitrogen cycle, making ammonia, nitrites and nitrates. The bacteria and resultant ammonia and nitrites are why water "fouls" when it is stored.

This is why most storage containers end up with slime and algae growing in them. There is, in fact, something for them to feed on.

Usually, we change the water in our storage tanks often enough that the amounts of ammonia and nitrites are negligible. And, after the containers have been around for a while, they have enough bacteria to complete the process and make nitrates, again in concentrations so low, we often can't meaure them.

Sometimes, the slime on the container gets thick enough to be a problem.

So, your container was probably not having enough flow through it, and as a result had an ammonia, then nitrite build up.

You can solve this problem easily by storing your water for less than a couple of days, or aerating your holding tank, so that the nitrifying bacteria will have enough oxygen to complete the process to nitrates and you won't have to worry about the nitrites. The amount of nitrates should be neglible (less than 1ppm, depending on how long your store the water).

I had a similar puzzle years ago when I collected water from a very clean dehumidifier. After storing the water for 24 hours, it had 3ppm ammonia! Where could the ammonia be coming from? Out of the air? It was coming from the breakdown of the dust in the air. The lesson here is don't use water from a dehumidifier for fish tanks, unless you prefilter it through carbon to remove all traces of dust from the air.

[beenyoung]

Thanks! I will try that.

[Carol_Roberts]

If you have chloramines in your water and use a water conditioner like Prime, ammonia is left as a byproduct. You may have had a partially cycled storage tank where good bacteria was converting the ammonia to nitrIte, but had not built a bed of bacteria to conver nitrIte to nitrAte yet. . . .