Some would say that you don't need any test kits.

I use kits that test for PH, GH, KH, nitrates, and phosphates. After a tank has been set up for a while and I get a feel for the rate at which it uses nutrients, I test only once a month or so, and then mainly for nitrates.

I have an ammonia test kit but I have never used it.

Some test kits are good and some are not. Here's a link to an evaluation of phosphate test kits that I made three months ago. http://www.aquaticplantcentral.com/f...test-kits.html

Good luck!

Bill