Dave, It would be better to have the Ro water stored in a barrel and aged/aerated and heated to tank temp.. R/O water is going to be as cold as the tap water which can be really cold. To run that into the fish tank may chill the fish too much or could cause your heaters to run non-stop. I tried here with my breeders and the water just got too cold..Im on a well and the ground water is COLD!I am hoping to be able to convert this to being able to hook to an outside faucet, and then using the output from the good water to either fill the tank directly or fill five gallon buckets to fill the tank with.
AL