<a href=showthread.php?s=&postid=7753243#post7753243 target=_blank>Originally posted</a> by pmcustom
My test kit isn't a very nice one and it's old, so I don't know how accurate it is...a nice new one is next on my list. Anyway, I have a 90gal with about 20gal in the sump, approx. 130lb LR, maybe 50lb sand (enough to have about 1 1/2" on the bottom), and I grow macro if that matters. PH is 7.9, Alk is normal (that's all the test says), and I haven't tested for Ca yet, but I imagine it's very low, like around 100 maybe. My tank is very lightly stocked, though (2 clowns, 1 mandarin, a few soft corals, maybe 50 inverts total) which is probably why I've never been able to detect any ammonia, nitrites, or nitrates at all. I bought the rock and sand established, though. Or my test kit is worthless.