I am not one to very diligently test my water, I'll admit. But I've been having plant deficiencies and hair algae so I decided to test it. It's an API Master Test Kit, and the regeants don't expire until 2017... So anyway, I got a .25ppm ammonia reading. I got one on my pond in the spring, but it always has a little ammonia so I didn't think anything of it. Last time I used this test kit on my tank, it had .25ppm but that was following fish stock issues, so I didn't think anything of it. But right now?

This tank has been up for quite a while, and in the 3 years I've lived with my BF it has had fish in it constantly. We had a series of deaths a while ago, but no fish deaths since before Christmas, and although I added 4 zebras, that was over a month ago.

I don't feed heavily, it has a lot of plants, Biowheel 200 and UGV, Eco Complete substrate, 50%+ weekly water changes. I'm totally confused. Is it my test kit doing this?

8 Zebra Danios
3 White Skirts
1 Tiger Barb
2 Neons
Rainbow Shark
CAE
2 nerite snails
A handful of random snails


Now that I typed that out, I do seem to be finding quite a bit of empty snail shells. Is this whats contributing to that ammonia reading? Any reason as to why I would be getting a lot of dead snails? I do have a copper test kit, and have tested my tap water, and it is 0. And I have coral (softies) flourishing in my SW tank, but I notice I have snail issues there too. Is this a calcium issue? Our tap water has a TDS of 180. 0 copper.

Have you checked ammonia concentration against a standard? Say tap water, dechlor tap water, and RO or deionized water? See if those give you colors that make sense, if not, it's your test kit. The exp date on these things might be if unopened. I've gotten suspicious of mine lately even though it's not expired and have been meaning to make an ammonia standard to test it with... The colors with these test kits can be a little hard to distinguish too, IMO.

Ammonia could be from the snails, or is there any dead plant material floating around or perhaps caught somewhere you can't see? Or dead fish down somewhere you can't see? That can be a major cause of ammonia spikes.

Also, any nitrites? And are nitrates through the roof?

Not sure about the snail thing, I see in my tanks plenty of snail shells and plenty of live snails too, haha. I assume the invasive snails die pretty regularly so I think nothing of it.