I've been wondering what test kits (brand) I should buy.

I've found an API master test kit for $15.00 (includes pH, high-range
pH, nitrite, nitrate, and ammonia). Since basically any two kits
allone would cost this much, I think its a good buy. But I was
wondering if people have suggestions other than the API kits. I've
tried dip strips but have real trouble reading them since they never
seem to stop changing color.

I would also like a KH and GH test (I have very hard water). I was
told that I shouldn't care about GH only KH and that the GH tests are
worthless since the testube can never be cleaned well enough to get a
good second reading. I was wondering what peoples comments are on
this.