RO/DI help please

[zoanutty]

I replaced all of my Spectrapure 5 stage RO/DI filters at the beginning of this year, including the membrane. I did not use Spectrapure brand for any of them since I needed them right away and the LFS didn't have that brand. I used Dr. G's brand. Afterwards, I made approximately 200-250 gallons of RO before my TDS started creeping, so I replaced the DI last week. I had some DI left from a Dr. G's bag and although it didn't fill the canister where it was totally packed, it did fill it 80%. I had only made about 30 gallons of water and the TDS were again at 34, so I figured that the DI was bad since it had been stored for a while, or I did not pack it well enough. I went ahead and got a few Dr. G DI replacement pouches again and installed one, packing it 100%. Now, after flushing the unit for over 45 minutes, my TDS is still at 30. How can that be? What am I doing wrong??? The meter I am using is a handheld one off Amazon (see pic attached) because the two in-line meters that came installed with the unit would always read zero no matter what, and I didn't trust them. The batteries on those are now spent. I'll replace them today but I am concerned about them giving me false readings.

Side question: How many gallons should a DI canister yield anyway? I know it varies with the TDS coming in. Mine is usually at 328 before the membrane, and 9-10 after the membrane.

Any insight from any RO/DI gurus much appreciated!




Sent from my iPhone using Tapatalk

 

[Opus123]

A DI cartridge should get you around 450gals with an incoming tds of 10. Even then it shouldn't shoot up very fast. Mine will take months to creep up to around 5 or 6.

If your tds meter is still reading close to the same numbers on the tap and after the RO membrane then I would think the tds meter is correct. Doesn't seem right though since your TDS after the DI shouldn't be higher than what is going in, not at least on a new batch. Do you have a LFS or friend that could test the RO water before the DI just to make sure your meter is reading correctly.

 

[ClownNut]

depend, i only use 2-3 bags of DI per year, 1 tds before DI 0 after DI.
flush once per month for 5-10 mins, 40-50ish gallons weekly top off, plus 50-100g water change per month. i guess, i am getting around 1000-1200g per DI.

 

[Buckeye Hydro]

I replaced all of my Spectrapure 5 stage RO/DI filters at the beginning of this year, including the membrane. I did not use Spectrapure brand for any of them since I needed them right away and the LFS didn't have that brand. I used Dr. G's brand. Afterwards, I made approximately 200-250 gallons of RO before my TDS started creeping, so I replaced the DI last week. I had some DI left from a Dr. G's bag and although it didn't fill the canister where it was totally packed, it did fill it 80%. I had only made about 30 gallons of water and the TDS were again at 34, so I figured that the DI was bad since it had been stored for a while, or I did not pack it well enough. I went ahead and got a few Dr. G DI replacement pouches again and installed one, packing it 100%. Now, after flushing the unit for over 45 minutes, my TDS is still at 30. How can that be? What am I doing wrong??? The meter I am using is a handheld one off Amazon (see pic attached) because the two in-line meters that came installed with the unit would always read zero no matter what, and I didn't trust them.

Any insight from any RO/DI gurus much appreciated!

First, let's start with THREE separate TDS readings:
1. Tap water
2. RO water
3. DI water

Run the system for at least 2 minutes before taking your RO or DI readings. Use a squeaky clean glass sample container for the TDS readings. Don't touch the inside surface with your fingers. Best to use a container straight out of the dishwasher.

Let's start there.

About half the time we field these sorts of questions from customers the "problem" ends up being inaccurate TDS readings.

Russ