# Ro/di



## royy (Jan 4, 2010)

I replaced my RO membrane recently and had a feeling my TDS was not 0. 
I purchased a TDS meter and it just came in today, and its saying that my RO water is 20-21 TDS while my tap water going in is at 150 tds. 

I have not changed any resin besides the RO membrane itself. It is a AquaFX Octopus with Booster Pump. I use a 100 gpd with roughly 80 psi. (The RO MEMBRANE IS ALSO AQUAFX) 

Is it time to change the resin? Or is something wrong with my flow? (flow restrictor?)


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## RR37 (Nov 6, 2012)

How old was/is the unit ? I change resin and blocks 4-5 times before swapping out the membrane.


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## royy (Jan 4, 2010)

8 months old? 

Okay i guess ill change it then. Thanks man.


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## supershrimp (Dec 29, 2011)

I think something is wrong , and it's not the di. My ro water goes in at about 460tds and comes out at 8tds that's before di. I'm sure your unit should be able to get a lower final number then mine as your tap tds is a fraction of mine. 

IMO if you just focus on changing the di, it will work for a while but it's going to be exhausted really fast. Di is just for a final small finishing touch. 

Again something is up with the membrane or the tds meter. 

Have you measured the waste to production water , for a 4:1 or whatever your unit calls for?


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