cleaning up mud
Member
Which ones do you use and where do you get them. Do you rinse/reuse or just replace them? Where is your ppm count?
How many are in your system?
How many are in your system?
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RO Membranes
- Thread starter cleaning up mud
- Start date
I use Dow Filmtec and have been buying these from Kleen Rite. I have not had success in rinsing/reusing them... too complicated and time consuming. I change them whenever the count gets to 3 or higher.
MEP001
Well-known member
You don't rinse RO membranes. They can be cleaned with an acid, but that usually increases TDS, and the cleaning costs about half of what new membranes cost, so it's not worth doing at all IMO.
I've always used the Dow Filmtec, and if everything is working right they should last 10 years.
Just in case you're referring to the prefilters, do not try to rinse and reuse them.
I've always used the Dow Filmtec, and if everything is working right they should last 10 years.
Just in case you're referring to the prefilters, do not try to rinse and reuse them.
I know you don't "rinse" them... as I said a complicated process that is not worth the trouble. Here is the cleaning procedure from DOW: http://www.dow.com/webapps/lit/litorder.asp?filepath=liquidseps/pdfs/noreg/609-00388.pdf&pdf=true
I change them whenever the count gets to 3 or higher.QUOTE said:That's interesting. Are you referring to PPM? If so, instead of throwing them out send them to me
No kidding - what pressure are you pushing your source water through at? I run mine between 150-175psi. I can't achieve 3 or less.
MEP001
Well-known member
I was mainly replying to the OP who asked about rinsing/reusing them - if a system has a flush, it rinses them anyway.
I change them whenever the count gets to 3 or higher.QUOTE said:That's interesting. Are you referring to PPM? If so, instead of throwing them out send them to me
GPG (Grains per gallon). GPG = PPM/17.1 anything over 3 GPG I would consider hard water. I also cross check by performing hard water titration.
Grains/Gal mg/L & ppm Class
<1 <17.1 Soft
1 - 3.5 17.1 - 60 Slightly Hard
3.5 - 7 60 - 120 Mod hard
7 - 10 120 - 180 Hard
Over 10 Over 180 Very Hard
I don't run softeners. Use the RO for presoaks and spot free. Reject water for HP rinses. That's why I am more concerned with GPG.
Water Hardness (GPG - Grains Per Gallon). The TDS count includes both hard and soft solids. I use a kit from Hach to perform hard water titration. In between titration tests, I use the attached chart to monitor the TDS on the RO system display. I do not change membranes unless the titration test indicates a water hardness > 3GPG.
I've used Filmtec and currently use one from GE. When mine get fouled I acid/alk clean them until I am unable to maintain less than 25ppm. I clean them about every other year.
I have a 50% recovery rate at approx. 150psi and a temperature around 75 degrees. There are membranes for cold water out there too. I use softened water. I have had membranes last around 5-7 years. Keep chlorine from getting to the membranes, they will get damaged.
You should get about .8 gallons per membrane. I have a single membrane unit and a 3 membrane unit which I added a 4th membrane to the unit last year
I have a 50% recovery rate at approx. 150psi and a temperature around 75 degrees. There are membranes for cold water out there too. I use softened water. I have had membranes last around 5-7 years. Keep chlorine from getting to the membranes, they will get damaged.
You should get about .8 gallons per membrane. I have a single membrane unit and a 3 membrane unit which I added a 4th membrane to the unit last year
