Yeah, buy a TDS
meter to go with it so you can see how any solids are in the water coming in and the water coming out. You obviously want 0 coming out, so once it starts rising is when you want to get new filters. You may not get them when your TDS
meter shows 1 PPM
or something, but 0 is ideal and anything more means your filters are starting to be done. I think, but don't hold me to it, that just plain RO
water is somewhere around 30PPM ish. So the DI
part brings it all the way to zero.
I just hook mine up to my hose, but someday when I have some extra time will do a more perm install. Would be real nice to hook up inside and to a top off and all of that.