Tropical Fish Forums

[IcePassion]

I have a new 55 g tank which has cycled, supposedly. I have a suction cup-affixed ammonia gauge which has read 0 ammonia for two weeks. Nitrite has been at 0 for two weeks (Tetra Easy Strips). So I started stocking. I have a few cories in there right now, that I put in there last week. They seem to be healthy and active.

However, all week, the API test I've been using has been showing slightly green (not even the .25 shade for the most part - slightly less green than that). But nitrites are consistently 0 (nitrates are also low). It's a moderately-planted tank with low-light plants.

However, the API test will never come back yellow (0 ppm). It's leveled out at what appears to be just under .25 ppm. The suction cup gauge still reads very clearly 0.

My thought was that maybe it's just baselining at slightly green, and that it's really 0. I just tested my tap water to see if I got the same result, and it actually came out at between .50 and 1.0 ppm.

Has anyone else had an issue with the API ammonia test reading slightly green with 0 ppm ammonia? Any ideas what's going on in my tank?
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Prolific grower of algae

[diademhill]

Could be ammonia in the tapwater - try a test on bottled water?

What ammonia level did you cycle the tank at?

[IcePassion]

It was 0 according to the hang-on-the-glass tester, which is why I added the fish (which seem to be doing well). But when I did a test a few days after adding the fish, it read at not quite .25 ppm, and has never since come back yellow - always with a slight green tint. Nitrates always come out at 0.
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Prolific grower of algae

[diademhill]

Your tank is NOT cycled.
Try testing nitrites again.

To cycle a tank you need to run it with an ammonia source for about a month. Your tank only started cycling when you added fish.