Fast DI Resin consumption/ 3rd membrane

[Poseidon Black Sea]

Hello recently i upgraded to a new RO/DI unit and it s great but i have some questions. First i am running well water and the TDS after the sediment and carbon filter is high 300-260 TDS prior to the membranes .
The first membrane is rated to 100Gh (used for 6 months by the previous owner) and the second membrane linked in series is 75Gh(new) .
The sistem makes 10Lites /22min of product water and 10 Liters /27 min of waste water. It is fast. Thing is after like 3h of use i already have like 1 third if DI resin used :(

Should i put a third membrane linked to the product water before the Resin chamber?
I ordered some pressure gauges next month they ll arrive:)

 

[KStatefan]

Well water can contain CO2 that will consume DI quickly.

 

[Hishman]

what’s the TDS after the membrane. A 3rd won’t help.

As others have said well water usually has a lot of C02 that is too small to be caught by the filter or the membrane.

Measure the alkalinity, ph, and TDS after the membranes but before the DI resin and put the numbers in the below site to calculate how much c02 is killing your DI. If it’s a lot you have 2 options. Fill a large container of RO water and bubble an air stone overnight then run it through the DI. Personally I would run valves and T fitting to your booster pump so you can have it pump the container through the DI. Option two is buy a dual stage DI resin canister and run anion and cation resins separately. The C02 will eat the anion and you’ll replace the cat/mixed bed resins less

https://www.hamzasreef.com/Contents/Calculators/CO2DIDepletion.php

 

[jrawk1120]

Well water is hard to combat. I think I had a few di canisters that I was refilling every other month. It’s just the nature of the beast. Get some canisters that are refillable and buy it in bulk.

There are some contaminates that need extra screening. I forget which.

Very possible to get to zero. Just takes extra.

 

[Shirak]

Make sure your RO is working properly. Should be around 4 or 5 tds before the DI. If all good there then you can run the RO into a big container and aerate overnight before pumping through the DI canister with a small submersible pump the next day. That should get rid of a lot of the CO2 which as mentioned will eat up the anion resin in your DI canister.