I use Salifert test kits for Alk, CA and Magnesium.
You should also get some cheaper kits to test the PH, Nitrates, Nitrites and Ammonia. I use API for those and here's a link to the kit of those testers:
I agree with using Salifert for testing Alk, Ca, and Mag. They are the easiest to use, and the easiest to read. I agree with using API for Amonia, Nitrites, and Nitrates. The only thing I would challange is the use of an API phosphate test kit. I use all the same test kits, for all the same tests, except for phosephates. I have one, and I tried using it a couple of times, but the resolution is so poor, that by the time it will detect phosphates, they are soo high, that it is an obvious issue. Levels have too be way above acceptable levels to even register on the kit. By then you would have hair algae everywhere. You have to spend some money on a lab grade phosphate test kit, like a Merc, to get a usable one. They cost about $100. I can usually tell by the polyp extension, and the color of a couple of my corals, without even using a $1 per test Merc test kit, when my phosphates are climing. I immediately change my Rowaphos, before hair algae starts growing.. If you get to know your corals, a PH test kit might not be needed. If you need one, buy a lab grade kit like a Merc, or you are just wasting your money.