What you can't test for can
hurt you. Well, not you but your tank.
Just because a water is fit for human consumption doesn't make it suitable for a reef. The EPA drinking water standard for copper is 1.3 ppm. See how long your inverts survive at that level. A RO/DI takes the guess work out of it by eliminating all those elements that are not found, at least in major concentrations, in seawater. It also saves money as you don't need a hundred or so test kits.
Anybody know who makes a test kit for Ununoctium?
