Best top off system?

[lastlight]

Originally Posted by mike31154

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.

This is it exactly. I can get down to 0 for a short time if the membrane is new, 1 for quite some time and then anywhere from 2 - 10 in the first hour or so. If it runs all day it will very slowly go back to sub 5.

TDS for me stays far too high in the first minute. I can't afford to blast through resin like that. Once it's low... it won't creep all the way up to 200 if it runs frequently enough but you never know.

My thing with plumbing direct into ro/di has much more to do with costs of resin than it does with flood fears.