New RO/DI 30 ppm

[CrisisReef]

Hello everyone. I’m starting up a new tank and replaced the filter cartridges as well as the membrane on my RO buddy. After running the two cartridges I installed the membrane. I then ran that for 30 minutes as instructed before installing the DI component. My water is coming back around 30 ppm. Our tap water measured at about 150 ppm. I suspect the membrane is faulty and I plan to check the water coming out of the membrane without the DI component. My question is what ppm should I expect from just the membrane without the DI? Also if the membrane is faulty, do you think my DI resin is shot after being used with unclean water? I probably made around 2 gallons by now with the DI installed.

 

[chaples55]

Is that 30ppm after the membrane or after the DI resin? If that's after the DI, then yeah your DI is shot and something is very wrong.

I would expect anywhere from 0-5 TDS after the membrane for that starting TDS, though it could be more if your water pressure is really low. It needs to run for a bit to build pressure before taking the measurement. It's normal for the first bit of water that comes out every time you start the unit to have 20-30 TDS.

 

[CrisisReef]

Is that 30ppm after the membrane or after the DI resin? If that's after the DI, then yeah your DI is shot and something is very wrong.

I would expect anywhere from 0-5 TDS after the membrane for that starting TDS, though it could be more if your water pressure is really low. It needs to run for a bit to build pressure before taking the measurement. It's normal for the first bit of water that comes out every time you start the unit to have 20-30 TDS.

That is after the DI resin, but it was right when I turned it back on. The RO/DI had been sitting for probably 30 minutes not running but still hooked up. Does that mean that you should run the water for a bit without the DI resin every time you start it up? Or just the first time like I did?

 

[dball711]

Something is wrong, check how everything is hooked up and make sure none of the filters, cartridges or membrane are in backwards. Should be ZERO after the DI stage.

 

[chaples55]

Agree with Dave, double check everything. TDS after DI should always be 0. If any TDS makes it through the DI stage, then the DI is probably bad (or water is bypassing it somehow?). Should be able to tell if the DI is used up by the color of it too. New resin should be blue and it turns yellow/orange when it's used up.

 

[CrisisReef]

Something is wrong, check how everything is hooked up and make sure none of the filters, cartridges or membrane are in backwards. Should be ZERO after the DI stage.

I’ll make sure to check, thank you! The only cartridge that could be upside down would be the DI resin. The other two had an arrow showing which way it flows, the resin had no such indicator so I just plugged it in the way I thought made the most sense. Would an upside down resin cartridge cause this?

 

[dball711]

Regardless of the arrows, check every cartridge/insert. I don’t think the di cartridge backwards is all the problem. Are you sure the to meter is good or maybe the di resin is bad.

 

[CrisisReef]

Regardless of the arrows, check every cartridge/insert. I don’t think the do cartridge backwards I all the problem. Are you sure the to meter is good or maybe the do resin is bad.

Just got home and ran the system again. My membrane is spitting out water at 4 ppm now, and the DI measured at 0 ppm. I think I just measured a little too soon. Thank you so much for the advice though! Would you recommend running the membrane without the DI for a few minutes before making water each time in the future?

 

[chaples55]

Just got home and ran the system again. My membrane is spitting out water at 4 ppm now, and the DI measured at 0 ppm. I think I just measured a little too soon. Thank you so much for the advice though! Would you recommend running the membrane without the DI for a few minutes before making water each time in the future?

That would technically make the DI last a little longer, but might be a pain in the butt unless you install a valve to do so easily. I think most people don't bother (I don't). The DI cartridge on the RO buddy is small though, so up to you if you want to squeeze every little bit of life out of it