i've never done it for frogs, but i have used ro for shrimp. i just mixed it with de-chlorinated tapwater to get the parameters i wanted. there are things like fluval shrimp mineral supplement, but there is no specific "add 2 drops/gallon" formula. it's all trial and error with that stuff. mix, test, mix, test, screw up, start over, mix, test....it's a frustrating process....lol