[mark]

System I'm using cost about 10-15 bucks though many on this board believe way it's setup will crash the tank.

I've got a furnace humidifier float in my sump hooked directly to the output of my ro/di unit.

Read the cons being; will fail open and cause salinity to drop and the frequent cycling of a ro/di causes high TDS from the ro/di unit plus premature failure of the ro membrane. As to the failing open, had a similiar float style in the humidifiers of the houses I grew up in (plus the house I'm in now) and sticking open never a issue or even one I heard of, nor any problem in the year plus I've had the auto top-off setup. As for the cycling, had the filter in-use now well over a year and a half and TDS in always single digits even measuring the first couple of ounces but for once when it was around 20 and that was after not changing the pre and di filters for about a year. After I changed the filters, back to single digits, still from the original membrane.

Again, others caution this setup but for me it works.