You can buy ro water from grocery stores and fill your 5 gallon jugs for around 25cents per gallon. I did that before I got a ro unit. Way easier to just have a unit, and it saves me a little money compared to buying it all the time at the grocery store. Also Bang made a good point on another thread that grocery store ro units tend to let their filters go a little longer than we would, and certain things probably slip through. But silicates are SOOOO bad, and you can't really get that out unless you do ro. I think if you can't buy an ro unit, the grocery store ro is a good bet, or your local lfs, but they tend to be a lot more. Good luck, ali:happyfish
Oh, and switching to ro I noticed a HUGE difference in the corals, and less algae problems and the fish were a lot happier.-ali