RO unit..

[partypalooza5]

Is it 100% ABSOLUTELY necessary for a FO or FOWLR setup? I know there can be algae issues but would using tap water be truly bad for a SW tank? I looked everywhere and they say yes.. Just want to see if its 100% needed. Can I get away with a sediment/carbon block filter?

 

[BigMike75]

100% = No, recommended = Yes. IMO if I was going to use tap water I would come more close to doing it with FO or FOWLR not reef. I would test my tap water first for all of the bad stuff. It would be better to find out first before you tried it. Some places have good tap water and some don't.

 

[HN1]

No. It's not 100% required, but I wouldn't do it with tap. For a FOWLR, I'd just buy water at the grocery store for 35 cents a gallon. If you have a big tank and definitely if you want to keep coral, an RODI unit will be cost effective in the long run and provides you an extra measure of control within your tank.