RO/DI question

[richardhmc]

I just bought a RO/DI system and I have a few questions
-Is RO/DI beneficial to every fish?( including freshwater/saltwater )
-Is it a good idea to fill up every tank with it?

 

[Yanbbrox]

RO/DI water is fine for fish that thrive in low PH, discus are a prime example. You may need to add minerals to the water to make it fish safe depending on the fish. Be warned, PH may be as low as 5 depending on your tap water.