As far as the test results, ammonia and nitrite should read 0 at this point. Probably dont need to test unless there is a more serious problem.
Hard to gage the Phosphate from your pics (not a fan of API for PO4) but it looks acceptable. IME easier to tell by algae/cyano growth when PO4 are up.
Also hard to read your nitrate results, again IMO API is not a great test for Nitrates.
Really need to get alk and Ca test kit for corals. This is a MUST for SPS and LPS. The API kits are fine here and pretty cheap. You should be testing these 2 pretty frequently until they are stable. (ask eddie about the holy trinity)
It looks like you dose 2 part from the pics. how much do you dose and how often? Do you add kalk to your top off?
Looks like you've got plenty of live rock and sand to cover your fish bioload. How much do you feed and how often? I still say, get rid of the bioballs, nothing but trouble
If you're on a tight budget my suggestion is get alk and ca test kit and work on stabilizing those levels. Maybe get the fish store to test Mg for you to see if you are in check. Your next big purchase should be something to improve water movement....either mp40 or wp25 or wp40.
Overall your tank looks in pretty good shape, keep those regular water changes going. Good husbandry is the key to success in this hobby!