Alk - Salifert
Ca - Salifert
Mg - Salifert
No3 - Salifert
No2 - Salifert
PH - Salifert and Pinpoint Probe
Ammonia - They all kinda suck... Have Salifert, API, Jungle Buddies Strips, but typically use a Seachem Ammonia Badge.
Copper - Hanna Copper Checker LR and Seachem for cupramine.
Po4 - Hanna 736 ULR Checker
SG - ATC Refractometer with calibration fluid.
Since my incoming water has chloramines I use Hanna Total Chlorine and Total Ammonia ULR freshwater checkers to make sure my RODI is up to snuff.
Sure I missed a few things...