Ammonia in established tank

[yahooandgoogle]

Hi I have ammonia in my tank. It reads at 0.25. I do weekly water changes and regularly gravel vac. My tank is around 90 or so litres. With two fish.
My nitrate reads at 10, nitrite 0, PH 7.6, and ammonia like I said 0.25. I did my weekly water change today added stress coat to water, gravel vac and gave the decorations a quick scrub. Fish look healthy one is missing a couples of scales which I have treated.
What could be causing the ammonia? There is no uneaten food no rotten plants and nothing has died. Any help would be great. I will do another water change in the next couple of days. I usually use spring water with stress coat when I noticed the ammonia. I test with the API liquid test kit.


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[yahooandgoogle]

I know that tank is too small for two. But saving for a bigger one at the moment as the bills just keep coming in.


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[Fresh2o]

Have you checked your source/tap water for ammonia?
At 0.25 ppm I would not worry about it too much. A mature filter should be able to handle that. I used to have 1.0 ppm ammonia in my tap water. So, while doing water changes I was actually adding ammonia to the tank. However, the bioload was low and the filters were able to process it. Only when I did larger water changes (50-75%) is when I would detect a trace of ammonia and nitrite the next day. Otherwise, things stayed at 0/0/20 for the most part.


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[yahooandgoogle]

Thank you for replying. No I haven't checked tap water will do.


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[enrgizerbunny]

What kind of fish? This makes a significant difference in what tank is "too small" for 2 fish. What kind of filter are you running?

I'd comment on ammonia but it's been well covered already.

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