I've been talking about this in my tank thread, but I thought I'd bring this issue in here, for the water gurus to weigh in.

My 29g tank has been cycling for almost a month. I used about 10 lbs of LR, 15 to 20lbs of dry rock, and some of my starting water was old WC water from my 20L. I've been testing on occasion, and I know that my nitrites spiked over 5 (max of test kit) a while back, but according to the test, I still have ammonia. I'm using an API test kit.

To test the accuracy of the kit, I tested the ammonia of my established 20L (right) next too the test for my 29g (left). This picture shows the result:



To me, it looks like they are the exact same. Is it safe to say that the ammonia kit is slightly off?

Yeah, they look the same, but I'm not sure what color they are on that chart.

The chart said it was about .25 based on the color.

I did get confirmation that my kit is bad. I took it to Phishy Business and they did a proper test on my water. My cycle is complete, with 0 amm, 0 nitrite, slightly elevated nitrates, no phosphates, and a pH of 8.0.

However, it means that my tests for Ca and Alk are also likely to be off. I bought them at the same time as the ammonia, etc kits. These are API kits, which I now understand to expire within 6 months to a year. I think I'm only going to buy kits for Ca and Alk right now, because the pH kit shouldn't really be as bad (it is still accurate). I don't think I really have a strong need for the ammonia, nitrite or nitrates.

What is a good test kit that has a decent shelf life but won't break the bank? I was thinking salifert, but I'm open to suggestions!

Salifert is good, they're what I am using now.
I find their PH kit a little annoying though, just kinda hard to read and stuff.

Not sure what you're willing to pay, but DFS has the Instant Ocean Reefmaster set on sale for about $53, if you test weekly it'll last you almost half a year, the nitrate, phosphate, and PH tests I know use foil packed powder test chemicals, quite a long shelf life. I've used them in the past (when they were Aquarium Systems) and really liked them.

I have an expired Salifert calcium kit and one for alk also, I can't recall when I got them, but the results on them match the LFS, so I'm assuming (bad word) they are still usable.

Its my opinion to test nitrates regularly, although with good nutrient export (macro-algea, good husbandry, and possibly skimming), nitrates should stay pretty low, I just like to keep an eye on it. Same with phosphates (which you didn't mention having a kit for).

Well, in my 20L, I have no fish and I target feed infrequently, so there isn't a big source of nitrates. I'll have to look into the IO kit. That doesn't sound like too bad of a deal. Oh, and I do have an phosphate test, but I am now forced to consider it also suspect. I've never had trouble with phosphates though, so I rarely test for it.