Planted Tank Guru
Join Date: Jan 2010
Location: Contra Costa CA
Pretty much all the test kits available to hobbyist aquarium keepers are adequate but not lab quality. There are ways to calibrate these kits, and learning some tricks to using them more accurately will help.
If you cannot find the kits you want locally, look at on line sources such as Drs Foster and Smith, or Big Als. There are many more sites, but these are the places I have found the best pricing on most aquarium supplies.
I would get started with these kits, calibrate them per the instructions here at Planted Tank, and see if they are helpful to you.
If you want to get more precise with the hobby, then look into lab quality testing equipment. These are not usually available at hobby sites, and you may have to google to find them. These are significantly more expensive, and I do not think it is worth it for what I want to do, but some people do want that extra precision. I would not suggest a beginner invest that much money when the hobby quality kits can be used in an efficient enough manner to do what we usually want to do.