[mike31154]

Plumbing ATO directly to RODI system probably works fine if your tap TDS is 10 or less like many folks on the west coast are fortunate to have. No way I'm doing that, not only because I don't trust direct hookup even if there hasn't been a flood, but also because my tap TDS is 210 or more. It only takes one flood to ruin your day, or crash your tank. Might as well use treated tap water like I did for the first year my system was set up. I was never any good at horsehoes and with my relatively high source TDS, it takes the membrane a while to get that down to an acceptable level.

As mentioned, my tap TDS is 210+ & I've observed my dual TDS meter showing around 180 TDS after RO when I initially turn the system on. It then takes a good minute or more (depending on time of year) to get down to a TDS of 2. After a few more minutes it finally gets to 1 TDS. I usually check again after about 15 minutes and during the colder months, the output of my 75 gpd membrane is then down to 0. All this tells me that if I want my DI media to last longer, I'm better off making my DI water in large batches. The first few gallons I produce are always diverted as RO only for drinking, cooking, coffee etc. If I were to run my ATO directly off the RODI, with short bursts of water produced governed by my top off, I'm pretty sure I'd be going through DI media like there's no tomorrow. I'm on a fixed income and can find better ways to spend my $$s.