I did a search and found some threads with some good answers. Here's one. I was trying to find some with responses from people that I've seen that are very active here.
Ive got a FOWLR tank and am using API test kit for saltwater tanks- I've used the tetra test kits also, not bad. I need a phopahte and calcium test kit, for those I will use the Salifert test kits, those are expensive, but worth it.
When I first started this hobby a few months ago I bought a Red Sea Marine Lab test kit because the kid at P#tco said it was the best they had. I used it religiously but had no way of knowing if it were "good" or not until a few weeks ago. A friend of mine who was getting out of the salt water hobby had another brand and gave me what was left of it and I get the same results on both so I guess the Red Sea is accurate.
Sue