I have mixed reef, after using different test kits and doing research, and figuring out best mix of accuracy, cost, and ease of use, here is where I landed:
Hanna: Phosphates, Alkalinity
Salifert: Nitrates, Magnesium, Calcium, and pH
Refractometer from Amazon: Salinity
TDS meter from Amazon: RODI water TDS
Hanna: Phosphates, Alkalinity
Salifert: Nitrates, Magnesium, Calcium, and pH
Refractometer from Amazon: Salinity
TDS meter from Amazon: RODI water TDS