DI Exhausted


I'll rent that test kit from you once you're done. Been following this since I'm experiencing a similar situation.

4 stage system. TDS of water into RO stage = 146. TDS out of RO = 3 for 98% efficiency. Lucky to get 250 gallons of '"0" TDS water from a pound of DI resin.
I used to use Spectrapure MAXCAP resin and got about 500 gallons from a pound of resin. When they stopped selling maxcap in bulk, I switched to BRS resin and saw the drop in longevity. Tried a few others since with the same result. Was going to try buckeyehydro's semiconductor grade next, but doubt that it will last any longer.


Well-Known Member
BRS Member
Well I got my water tested, source water is 22ppm, 0 after the DI. BRS says under 15ppm is on the low end, over 35ppm the high side.

This sucks!


Well-Known Member
BRS Member
So a little update on this if anyone cares. I installed a second DI unit and my plan there was to ensure I was fully exhausting the first DI but not risking bad water for the tank. I had an unscientific thought that it was possible that the resin looked exhausted but wasn’t.

Well I’ve been running it for a while and the first DI stage if fully brown and putting out 1tds. Ida thrown this out 50 gallons ago easily. The second DI confirms 1 tds coming in.

Long story short, I’m getting a lot more life out of the resin running it this way and I don’t feel like I’m jeopardizing the product water I’m using.

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