Why R/O unit?

[sacsalt]

I am new to saltwater and am wondering is r/o unit required for saltwater? Why?

 

[alix2.0]

not required, but reccommended.

 

[jackri]

It makes life SOOOOO much easier when you do. Here's a thread I did awhile back to help demonstrate why it's a good idea
https://forums.saltwaterfish.com/t/351021/this-is-why-you-need-ro-di-for-your-reef

 

[sacsalt]

Wow, that is a nice post you made there, it shows me a clear picture of a r/o unit in action. I see why i need it now and will get this r/o unit thanks.