Yea I was trying to conserve space by using 1 tank for RO water. By mixing in the salt on say Friday morning and not "allowing" the top off pump to run in that period I could do water change Saturday morning and go back to ATO with freshwater after that. This is just a tiny room but I will find room for one. And if not I will add some more electronics and do it anyway. Thanks Ashlar said:Cormin,
Check out the container in this link, they are pretty narrow and hold maybe 14G each and really saves on space. You can find them in the container store. http://www.melevsreef.com/plumbing/auto_topoff.html
Cheers,