water wasted when using RO/DI filter, is it normal?

[ljuhl]

I've just tried to use my new RO/DI filter and I wasted AT LEAST 10 gallons of water for each gallon of filtered water. Is it normal or did I do something wrong?

 

[taikonaut]

The ratio of waste water to filtered water is around 4:1, depends on water temperature and impurity. 10:1 is a bit high, so you may want to check and make sure the regulating valve that control the rejection ratio is not clogged or misapplied.

 

[WannaBeReefer]

I had the same problem! I am on a well and do not have super high water pressure. My Kent system said best performance can be achieved at 90-110 PSI, I was at 40. So I bought a pressure pump to help it out a bit, now it runs at 90 PSI and my waste water is less but not great, at about 7 to 1.

I live in the North East and its been cold, my water temp is around 55, recommended water temp is 70. To get around the temperature thing I purchased a 60 foot peice of 1/4 tube ( I tried 25' but I still had very cold water) and replaced the short fill tube, I filled a 5 gallon bucket with warm water and tossed in a heater to maintain the temp, submerged the 60 feet of tube and presto! 70 degree water going in. I think the temperature helped far more than the pressure. I am at 3 to 1 now.

Thanks to Kent Marine for the idea!
HTH

 

[Anonymous]

My pressure was always low also; I called the mfg (Aqua-FX) and the guy said that number was just to get the appropriate gpd, it didn't affect the performance otherwise if pressure is low.

 

[taikonaut]

Well, the positive side of this is that at a great rejection ratio, you are getting better water from the filter than at smaller ratio.

 

[abbeyspal]

I am a dialysis tech. we use an RO that produces up to 2000 gallons daily. I have no experience with home units but in theory you should only have to waste 50 percent of your water to create your product water. Just my two cents though.

 

[taikonaut]

Commerical RO units use a slightly different membrane setup than residential RO unit. It enables it to have a much lower rejection ratio. For residential setup, the ratio is arround 4:1.