[Myka]

Elos kits are kinda pricey (depending what you compare to lol), but they are really easy to use and to read. Salifert kits are good too. API are pretty straight forward, but I would prefer a higher quality kit (their Mg kit is pretty good imo). Generally though, hobbyist grade kits are not overly accurate. Buy 3 kits from the same manufacturer, but from different batches, and you will get 3 different numbers from the same water sample. I have had kits vary by 100ppm (Ca), and 3 dKH. Annoying as "heck".

You hear people talk about "the big three" when it comes to testing which means Ca, Alk, and Mg. I think that Nitrate and Phosphate kits are also important, but don't need to be tested very often (kits will often expire before you use them up), so often I recommend people to just take a sample to their LFS for testing once a month or so.

I wouldn't be too worried about the pH for now as I suggested earlier, but I agree that you will need to calibrate your pH monitor before you trust it. Most will not be accurate out of the box. You will need pH 7 and pH 10 solutions to calibrate for alkaline pH as in our marine aquariums. Fyi, for freshwater aquariums that would be reading acidic pH you would use pH 4 and pH 7 solutions to calibrate. Personally, I like the single use pH calibration solutions offered by Milwaukee which should be available at any good retailer.