New to mixing my own salt and was wondering why salinty levels vary from a fish only tank to a reef tank. It is my understanding that a fish only tank can sustain with a lower salinty level than a reef tank. I have a reef tank and aiming for salinty in the 1.024 range. Also does anyone buy RO water from a store or a dispensing machine? I am leary of doing this as do we really know if it is filtered properly but I currently have no choice. Hoping to set up my own RO unit at the house soon but have a few other things to work on first.