RODI Unit Issue

[kita_katan]

I just got a LiquaGen – 5 Stage RODI unit and I just hooked it up and after flushing it out for 20 min I started it up and ran it. The ppm meter is still saying 13 ppm and it won't go any lower. I have been running it for about 3 hours with the same result. I do not have a PSI meter, that will be here on Wends, but I also do have a shut off valve to control the water flow going into the unit. When its wide open it goes way up into the 20's so I kept adjusting it until the best I can get is 13.

Any suggestions?

 

[spscrackhead]

What is tds before the unit?

 

[kita_katan]

Its at 368 ppm.

I will try to flush it for an hour and then see what it is reading.

 

[TangingOut]

Is 13 after the membrane or DI stage?

 

[kita_katan]

DI Stage

 

[TangingOut]

Well your DI resin is now used up. Probably been sending high TDS through it. I would test the TDS out of the membrane to ensure it's rejecting AT LEAST 95% of that 368. If not then something is wrong with your membrane. Try that next. Also what's your waste to product ratio?

 

[dream54ing]

Well your DI resin is now used up. Probably been sending high TDS through it. I would test the TDS out of the membrane to ensure it's rejecting AT LEAST 95% of that 368. If not then something is wrong with your membrane. Try that next. Also what's your waste to product ratio?

+1

Did you get unit used?

 

[joeyf]

Man, a TDS of 368 would be nice! Mine runs +/- 900 going in. It comes out ~30 ppm from the RO membrane (97% rejection). I have a spectrapure maxcap, so it goes in to the maxcap cartridge with 30, and out with 0. The silicabuster doesn't have to do much. I could get lower numbers from the membrane if I added a booster pump, since my pressure is only ~50 psi.

I think knowing the pre-DI TDS reading would help to figure out what's happening. It's really surprising what a difference the water pressure makes on the quality of your RO product water.

 

[azsoccerpop]

can someone explain why boosting water pressure to membrane increases its efficiency? I don't understand how increasing water flow reduces the wasted and improves membrane life & output

 

[epon]

can someone explain why boosting water pressure to membrane increases its efficiency? I don't understand how increasing water flow reduces the wasted and improves membrane life & output

the membrane works most efficiently around 90 psi iirc, tap pressures are usually 60 - 70.

 

[kita_katan]

I was mistaken, we had the reader before the DI chamber, changed it to after and at 0 -
Thanks for all the help