I have a 50 gpd Pure-flo-II RO unit. I just replaced my RO membrane for the first time. I also replaced the micron and carbon units as well so the unit should be as good as new. The ratio of water should be 1:3 (clean:dirty) but i am now finding it is about 1:1. It is a little slower on the clean end but not close to the 1:3 ratio it should be! What do i need to do? I have read that the membrane may not be seated right it appears to tightly go into the housing? Please help!
Matt, 1:1 ratio is great, your using less water. Is the end water still coming out with 0 TDS? if so then the unit is doing fine. If not check your RO TF membrane. Did you put it back in the rigt way?
My TDS meter needs batteries. I just ordered some new ones. Is it definite that if the TDS is zero coming out that the unit is working correctly? I will test and post as soon as i get more batteries. Is it possible for a 1:1 ratio? I though that RO units always produced more waste water than pure?
if it is ro and di wont tds be zero as long as the di is ok? even if the ro system doesn’t work right it will just deplete the di faster? is it possible to test tds before the di resin? Or will di just remove most tds if it is high out of the ro system. also morty do you have a permeate pump on your ro system??
you must have a leak somewhere. seating the O rings on the membrane? 1 to 1 is just not the design spec of membranes. so i would open up the housing and try to reseat the membrane and all other fittings.
I have been using a Pure-Flo 50 for 12 years. Actually i upgraded it to a 75 GPD 6 years ago. Just buy a 75 membrane and the matching discharge Ristricting Orifice to create the correct back pressure and its done. same housing.
Anyway, 1:1 is not possible with membranes. should be more like 4 to 1 reject/product. so you are getting some water bypassing the membrane. clean the groves and O-rings of dirt and such. try again.
[quote=“dunk, post:4, topic:4464”]
if it is ro and di wont tds be zero as long as the di is ok? even if the ro system doesn’t work right it will just deplete the di faster? is it possible to test tds before the di resin? Or will di just remove most tds if it is high out of the ro system. also morty do you have a permeate pump on your ro system??[/quote]
I think your thinking is right. you could do it with di alone (bring tap to 0tds) but it would cost a fortune in resin. So thats good to point out, 0 tds final product “could” just mean your di is working OT.
If you want to know for sure 100% you need to check the tds goin into the unit (tap water) and the water coming directly out of the ro membrane. do some math acc to the membranes rejection rate and you’ll see if its working properly. ex. if you have a membrane with a 98% rejection rate, with tap water at about 220 tds then the water coming out of the membrane (before the di) will be around 5- 10 tds. and the di will polish off that little amount easily.
Ken’s right though, not possible… unless you’ve got some super high quality tap water to start with (not likely around here) >::: Let us know what you find out when your batteries arrive!
Check the flow restrictor…according to spectrapure its important that you get the waste water to product water ratio at about 4:1…
the restrictor may need to be changed .
Gotta agree I only have about 37 TDS going into my RO and mine is still almost 3-1
I'd check to make sure the membrain is seated properly and also make sure it is the same dimensionsruss at buckeye field supply. com is the best guy in the world for rodi issues. he saved me over $100 by telling me not to buy a booster pump. he can hook you up right and for the best price. once he actually refunded me $$ on shipping AFTER i had already paid it. i am exactly at 4:1 thanks to him
I’m also having some problems with my ro/di. I bought a 6 stage 100gpd from purewater.com. about 6 months ago and checked my tds and its reading 20ppm at the output of the filter. So my question is what would cause that? Is my di resin done already?
If your TDS is that high on the output your DI resin has probably crapped out. 6 months is about the time to start changing out filters but that depends on what your TDS is going IN to the unit. If your prefilters have clogged or aren’t seated right then you’ll use up DI faster.
It’s definitely time to change out the filters and DI resin though. I don’t like my TDS over 3-4.
[quote=“beadlocked450r, post:10, topic:4464”]
I’m also having some problems with my ro/di. I bought a 6 stage 100gpd from purewater.com. about 6 months ago and checked my tds and its reading 20ppm at the output of the filter. So my question is what would cause that? Is my di resin done already?[/quote]
Do you know what the TDS is going into the RO unit?? If it is high enough and you have used it alot yes it is possible to be used up in a short amount of time.
Also do you have that high of a demand for ro water?? The system I had was over 300 gallon combine not including the other tanks and I have a 60 gallon per day and it's more then enough. The higher the out put usually the effiency of the RO is low.My Ro is a custom set up it’s a 5 stage Hague system. With a 22 g storage bladder system. I installed two whole house filters in series. A sediment and a carbon after two years I sterilized the Ro and repl filters and all looked brand new. It’s 7 years now and haven’t done any thing to it. Tds in is 160 out is about 12 this is higher due to Tds creep from the permeate pump. It then supplies the refrigerator and the bar sink. From there it goes into two di filters in series. They are color change resin filled. When the first is brown and I notice it I change it tds is always 0 I do not store water in a container which is nice. I replace di about once every 200 gallons approximately. At 12 tds
I would run at least 5-10 gallons through the Ro after filter change before testing tds. The carbon post filter needs to be flushed. Also do not drink Ro and di water it’s bad for your health.
Oh if u don’t know this bulk reef has the canister for di resin it’s $7 and the color change resin is $11 I think so it’s so much better than spending $40-$60 for a replacement. When u see the brs version it looks confusing how it works. But it’s very easy and cheap. A ten inch cartridge will fit perfect in any ten inch canister.
Still waiting on the batteries! I am going to try to reset the membrane tonight and see if that helps. Ken when you replaced the membrane on the 50gpd unit what brand/type did you buy. This is what i bought:
The Dow Filmtec TW30-1812-50 RO Membrane Specifications:
Dimensions: 1.75" x 11.75"
Max Operating Temp: 113 F
Max Operating Pressure: 300 psig
Max Feed Flow Rate: 2 GPM
Max Feed Silt Density Index (SDI): 5
Free Chlorine Tolerance: <0.1 ppm
NSF/ANSI Standard 58 Tested and Certified
They say that it is combatible with the unit i have. I only have a 2-stage unit (micron and a carbon) then the membrane. Can my leak be coming from somewhere other than the membrane?
Filmtec is supposed to be the best membrane. Personally I would add a di canister to it.
I may do that. Now i am just trying to figure out why its producing 1:1 pure/waste water. When i do test for TDS if it is near zero coming out of the pure water side does that mean everything is working correctly?
If it’s zero with a 1:1 ratio then wow that’s great. I think it won’t be. I personally think it’s a bad restrictor. If the membrane isn’t seated right I think water would pour right out, of the product. Now have you tested the ratio before? If u have and it’s different then I would say you made a mistake doing it. Buy if u haven’t there is no need to think anything. Now with the ratio being 1:1. Your gpd is 50 how long does It take to fill a gallon jug should be 30 min app. If it fills faster that is too fast and may be the membrane seating if it’s slower I would look at the restrictor.
It fills a gallon jug in approx 20 min. So that is 3 gallons an hour which equals 72 gallons a day? The unit and the membrane are designed for 50gpd. I have reset the membrane three times and there is nothing really else i can think to do. I will still test the TDS when the batteries come in. I am filling it from a garden faucet and the water is probably around 80 degrees. I know the more pressure and the warmer the water the faster it passes through the membrane. I guess now i just wait on the TDS readings before and after. Unless anyone can think of anything else. Thanks