Didnt think to look on ebay for reviews good idea. I was surprised to see 150 gpd single membrane unit for under 100 bucks. Standard size filters and ~1.1:1 waste to filtered ratio to be one of the lower waste units (from what I've researched) out there is nice too. 3:1 seems to be the norm.
Im reading the same info on dual DI
Capt. The general consensus seems to indicate the extra DI
is a waste. Read somewhere that a DI
can sometimes start channeling so perhaps its a fail-safe add-on. Might be good for auto-topping where you wont be checking output with TDS
meter. Unless of course you have some sort of TDS
controller with auto-shutoff.