Budget RO membrane
- Thread starter jdpeters
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The simple answer is that you’ll be letting 3% of the TDS through, vs. 1%…
This said, you’ll go through DI resin roughly 3x faster!
The cost-benefit analysis may be worth doing, but given how long Dow Filmtech membranes last at 99-99.5% TDS rejection rate between changes, I doubt the cost savings on this budget membrane will show over its lifespan!
This said, you’ll go through DI resin roughly 3x faster!
The cost-benefit analysis may be worth doing, but given how long Dow Filmtech membranes last at 99-99.5% TDS rejection rate between changes, I doubt the cost savings on this budget membrane will show over its lifespan!
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jdpeters
Well-Known Member
That makes a lot of sense, thank you. So spend the extra 14 bucks lol
fish_collector
Valuable Member
Those cheap amazon membranes are ok for use in the ro under your kitchen sink but if you really want good quality water spend a few more dollars and buy a Filmtek membrane. There are no alternatives. You must use a fresh 1 mic sediment and (2) 1 mic carbon blocks before the Filmtek membrane but that is standard for any membrane. Your rejection rate depends on which flow restrictor you have, and you water pressure. Letting the membrane run for about 10 minutes before you send the water to your DI really helps to increase the capacity of the DI but you may or may not have already known that.
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jdpeters
Well-Known Member
I went ahead and ordered that. Thank you for the feedback. My PSI dropped to 50 so I swapped the sediment and carbon blocks which increased it by 5 and now I’m gonna see what it goes to after I flush the new ro membrane. I might add a booster pump.
fish_collector
Valuable Member
Cool, you'll like the Filmtek membrane they work well. I don't use a booster pump yet because my city water pressure is in the high 60psi range most of the time but balck friday is coming up and that has been on the want list. Last year I added a second membrane, and put together a 3 stage DI from parts I got on Amazon, and the resins from BRS. Currently I manually bypass the DI when I first begin to make water to allow the TDS to come into range, I've been looking at auto flush valves that would do that for me, sometimes I forget the unit is in bypass and all of the water goes down the drain 
. I'm kind of a water geek and monitor the raw water, pre and post RO for both membranes, and after each stage of DI. It gives me a good idea of what the unit(s) are doing and when sediment/carbon blocks need to be changed. And fwiw, my municipal water ranges anywhere from 500-900 TDS so I'm lucky to get anything less than 20 out of the membranes.
My buddy has 2 of 75GPD Filmteks and a booster pump, he reprocesses the waste of the first membrane to recover some of the water. Anyways he is making about 200GPD with the booster, the same as what my pair of 100GPD is making without so a pump is definitely the way to go. I'm hoping to see 250GPD when I add a booster to mine, as well as improved rejection.
Let us know how your new membrane is doing.
. I'm kind of a water geek and monitor the raw water, pre and post RO for both membranes, and after each stage of DI. It gives me a good idea of what the unit(s) are doing and when sediment/carbon blocks need to be changed. And fwiw, my municipal water ranges anywhere from 500-900 TDS so I'm lucky to get anything less than 20 out of the membranes.My buddy has 2 of 75GPD Filmteks and a booster pump, he reprocesses the waste of the first membrane to recover some of the water. Anyways he is making about 200GPD with the booster, the same as what my pair of 100GPD is making without so a pump is definitely the way to go. I'm hoping to see 250GPD when I add a booster to mine, as well as improved rejection.
Let us know how your new membrane is doing.
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