RO Membrane Help

[Madreefer]

Originally Posted by Myka

Since you're replacing your membrane, why not switch out the in line flow restrictor to either a 75 gpd or 150 gpd (if you have enough water pressure) and buy a matching membrane? The rejection rate on the 100 gpd membranes is terrible, and as mentioned, will affect your DI resin significantly Flow restrictors are like <$5.

It's already restricted down. I have the 200gpd unit.

[Madreefer]

Originally Posted by Madreefer

It's already restricted down. I have the 200gpd unit.

Oops my bad Mindy. I do have the 100gpd. Brain fart. I did have a restrictor in there before but I don't remember what it was. I believe I removed it. I will definitely be looking in to putting another one on there and thanks for posting that link Mark, that's good info. I'm thinking 50gpd if possible as I have a pretty big reservoir for RO water

[Myka]

Originally Posted by Madreefer

Oops my bad Mindy. I do have the 100gpd. Brain fart. I did have a restrictor in there before but I don't remember what it was. I believe I removed it. I will definitely be looking in to putting another one on there and thanks for posting that link Mark, that's good info. I'm thinking 50gpd if possible as I have a pretty big reservoir for RO water

You should have a restrictor in there to match whatever the combined flow of the membranes is. My system runs dual 150 gpd membranes so the restrictor is 300 gpd. The flow restrictor is what forces the water to go through the membrane. If you run the system without a restrictor, you will be causing lots of water to bypass the membrane and very little to actually be going through the membrane. Why would you remove the restrictor?

If anything, you can use a restrictor that is less than the combined flow of the membranes, but then you are causing the membrane to flush less than recommended. So say you have a membrane and system that run 1:4 ratio of good RO to waste. If you use a lesser restrictor then you may cause the system to run 1:2 or even 1:1. By preventing the flushing though, you can cause the membrane to prematurely clog up. So it depends which you prefer - membrane longevity or wasting less water.

[mark]

pressure and temperature effect the output from the membrane so if your not at the membranes specs, been reading using a 75gpd restrictor might not be the best match for a 75gpd membrane. Here talks about trimming the restrictor, can also use a variable restrictor for the change in temp with change in seasons to keep at the 4:1 waste ratio.

[Madreefer]

Ok I went and looked and I did not remove the restrictor. There was quite a bit of confusion when I purchased this unit. So I can't quite remember all that went on. It wasn't supposed to be sold as it was a prototype and was supposed to be for in store use only. I'll try to speak with Albert tomoro and see what he recommends. I would prefer the Vertex membrane but I have never seen any for sale until Tyler mentioned it in an earlier post. Thanks for all the suggestions

[mike31154]

It's unlikely that you will find a 'Vertex' membrane. Vertex, Aquasafe, BRS, Buckeye Hydro & most of the other names you see on RODI units are companies/vendors that assemble the systems from standard, generic components. In our case, that means 10 inch cartridge housings for all your prefilters as well as a standard size RO membrane housing. Apart from that, the only difference is what options each vendor provides for what price. Auto flush, pressure gauge, TDS meter etc. Most of these are 'standard' components as well, sourced from other companies that specialize in their manufacture. I recall seeing one vendor/'brand' out there that individually tests each membrane before selling the system, but you pay for that in final price & to be honest, I'm not sure it's worth it. It's still a DOW membrane.

It's kind of like large appliances. In reality there are only a few actual manufacturers out there and companies like Sears, GE, Whirlpool etc. simply have them built with their own logo, a few cosmetic changes to differentiate them from the competition and on to the showroom floor they go. I'd wager the compressor in every refrigerator out there, regardless of brand name, comes from across the pond to the east.

Quite certain the DOW filmtec membrane is pretty much the standard these days & it's what you'll find in most good quality RO systems, Vertex included. Might be another manufacturer, maybe even two, but they're up against a giant with DOW & unlikely they have the R&D department, let alone the manufacturing might at their disposal to provide meaningful competition.

[Madreefer]

Originally Posted by mike31154

It's unlikely that you will find a 'Vertex' membrane. Vertex, Aquasafe, BRS, Buckeye Hydro & most of the other names you see on RODI units are companies/vendors that assemble the systems from standard, generic components. In our case, that means 10 inch cartridge housings for all your prefilters as well as a standard size RO membrane housing. Apart from that, the only difference is what options each vendor provides for what price. Auto flush, pressure gauge, TDS meter etc. Most of these are 'standard' components as well, sourced from other companies that specialize in their manufacture. I recall seeing one vendor/'brand' out there that individually tests each membrane before selling the system, but you pay for that in final price & to be honest, I'm not sure it's worth it. It's still a DOW membrane.

It's kind of like large appliances. In reality there are only a few actual manufacturers out there and companies like Sears, GE, Whirlpool etc. simply have them built with their own logo, a few cosmetic changes to differentiate them from the competition and on to the showroom floor they go. I'd wager the compressor in every refrigerator out there, regardless of brand name, comes from across the pond to the east.

Quite certain the DOW filmtec membrane is pretty much the standard these days & it's what you'll find in most good quality RO systems, Vertex included. Might be another manufacturer, maybe even two, but they're up against a giant with DOW & unlikely they have the R&D department, let alone the manufacturing might at their disposal to provide meaningful competition.

Yea that all makes sense Mike. And i've never seen a vertex membrane. I replace the membrane every year and I go thru the same thing each time. For the life of me I can never remember which membrane to get. As I said before this was a prototype I was sold so no box or instructions etc. The first time I changed this membrane the one I took out was a 50gpd membrane. I seen that someone posted about getting a vertex membrane and that added more confusion. Note to self....never buy prototype equipment or stuff from fly by night stores.

[StirCrazy]

Originally Posted by mike31154

It's still a DOW membrane.

Actualy there are about 5 major membrane manufactures and a few smaller ones, Dow was the standard, could be still, I haven't looked at specks laitly, but most of the RO's we buy don't come with DOW as they are more expensive. actualy there are a lot more than 5 now, just looked it up, here is a company that sells a tone of different brands
http://espwaterproducts.com/resident...-membranes.htm

most companies will buy a generic 60/100 membrane and sell there unit as a 100gpd. well this system will put out 100 gal per day but only at 90 PSI water pressure and the right temp, at the test rate of 60 psi it is only a 60 gpd membrane. always but the membrane that will give you your desired output at 60 psi, unless you have a booster pump.

my RO came with two membranes, they were hydrotec 50gpd membraines, when they were done I replaced them with 100/160 membranes and bought a booster pump that would give me 120 PSI feed psi. I ended up getting 300 GPD out of this set up with cold water, there is a lot you can do just decide what you want and get the right parts. you can also use a flow valve as a restrictor, just takes a bit to set it up but it is more fine tunable, I used to set my system at 3.5/1 rejection rate.

Steve