List of things to upgrade to and are important:
Better test kits. Need to be able to test PO4 (I use a Hanna) NO4 low range, alk, cal and mag (I use Red Sea)
RODI unit or at least a good source of water from a friend or LFS. Personally I don't trust anyone's water but the water I make and I even make mistakes.
Those 2 thing will be a life savers to your tank. I keep 30 gallons of salt mixed and ready to go incase of any issues and I do the same with RODI water. I also check my Alk, Cal, NO3 and PO4 at least once a week and my Mag about once ever 2-4 weeks.