I guess if the TDS
was low enough, it could be used but for most, a RO
unit is used to get pure water for the tank. You are filtering it and then mixing it with the waste. I guess it might be cleaner than what you started with ... never tested that myself.
With a PO4
of .25, you will have algae issues at some point. The DI
filter will remove this but you add it back by adding the waste. Unfortunately, with the RO
, you waste water. There has been more than one thread on that matter alone.
Try it and see what happens. I used tap water for years on a FO
tank with no problems. I moved and upgraded to a bigger tank and went to a reef setup and then had red slime algae like crazy. The RO