That is the important bit, which-ever test kit you use.any time you measure an endpoint parameter for a kit, standard procedure is to then dilute the sample with RO water and test the dilutions
Fresh water is a bit different in that it varies from really soft and ion deficient (black-water) to hard and carbonate buffered (Rift Lakes etc.).I like the idea of 'calibrating' a test kit with RO, im surprised that is not something I picked up from the marine hobby.
Can anyone point me in the direction of a good set of test kit?
also i have some Salifert test kits from my marine tank, will these work the same?