RO/DI problem

Recetly upgraded to a larger RO/DI unit. I purchased the 100gpd unit from BFS and was happy after the initail break in was getting a TDS of 0.

After filling and rinsing my new 125 gallon tank twice with RO/DI water I started to get around 27 TDS reading right out of the RO/DI unit.

Why would the unit start to fail after only 350 gallons of water run through it?

 

Are you using the cold water line? Hot water will ruin the membranes.

 

What does the DI resin look like. IF it is not color changing resin you will never know really. 350G is a lot of water depending on how many stages your RO/DI has.

For example mine is a 7 stage so i have extra time to replace the sediment filters and color changing DI resin.

If you have single DI stage you will probably have to change it after 350 gallons

 

I have a single stage DI unit, I have run well over 1000 gallons through mine, still have 0 TDS and the color is still mostly black. And really I think he only ran 250 gallons through it, at least that was my math.

 

His DI resin is probably not the same as yours and his water is not the same and his RO/DI unit is not the same.

1000 gallons is amazing where do you get this special DI resin?

 

Ya, but I have 50 gallons or so worth of sump and fuge under the tank so it's about 175 total volume.

It's a 4 stage unit with 1 DI stage. TDS after the RO membrane was reading 36ppm. The DI resisn cartrige is color cahnging and now its a brown color at the bottom changing to tan and redish towards the top of the cartridge.

I had a old DI cartridge from my old 50gpd unit and decided to swap them and see if that helped and it dropped the TDS back down to 0. This cartridge had been used for 6 months and had probably done close to 600 gallons of water still reading 0 ppm.

 

Are you guys referring to the product or total water that has run through including the waste?
I've probably run 1000 gallons and my TDS is only 5. Tap is around 150-250.

 

I am talking about the product, not including waste. My tap water is in the 60's. the cheaper units with the horizontal DI will probably burn up in half the time as the vertical canister, but my canister has done pretty well. From thefilterguys.biz.

If the tds coming from your ro unit is in the 20's or higher then yes after 350 gallons your di resin will be used up.

 

lightning: The issue appears to be the high tds of your RO water (36 ppm). The "dirtier" your RO water, the quicker you will burn through your DI resin.

What is the TDS of your tap water?
What is your water pressure?

Russ