I'm pretty lucky as Neptune is only a 5 minute drive from my office. So I test my water there frequently. I do have Elos test kits for CA MG and API for Alk, but I can never get them to read as the same result as Neptune (i think they use Salifert kits). But overall, once you know your parameters are good, I guess you can use any test kit just as long as your are consistent with one, therefore getting the same readings.
Every tank is different. Take a look at this. This should give you a general idea on where to start.
http://reefkeeping.com/issues/2006-02/rhf/index.php