Quote Originally Posted by 350gt View Post
HAD TO UPDATE THIS THREAD AS THE LINK CHRIS POSTED WAS A GREAT TIP!!!!!.....


I have been doing this for awhile after he posted the link and its amazing how high the TDS is coming out of the membrane for a few minutes..... FOR me, it starts around 120, then drops to 6 or under within a gallon.....

within that gallon you are saving your DI RESIN from having to eat up all that TDS, which extends the life of your RESIN.... I sometimes bottle the water in gallons and store in the fridge for my own consumption...... IT A WIN WIN in my book....
This burst of not-so-clean water when you first turn an RO system on is caused by a process called "TDS Creep." Here's some data from a couple of runs with a 75 gpd membrane:


So given this, you can see why its a good idea to make sure your RODI system doesn't short cycle - meaning turn on and off frequently. When your system comes on, you want it to stay on for an extended period of time. So if you leave the water supply to your system turned on all the time, AND if you run your DI output to a reservoir subject to evaporation (or to your sump), the system will turn on everytime the float drops just a hair and opens. That's why we developed the Hi-Lo Tank LEvel Controller.

Russ