Ro Membrane /Main Filter

[2Biz]

Has anyone purchased RO membranes from the online company Allfilters.com? They advertise a little more production for the same size filter than Filmtech or some of the other brands at only half the pressure. My system runs at 190psi and they say they get more production at 100psi. I don't know how thats possible? Also price is less than half to almost 3x less than KR's Filmtech or Dultmeier's name brand filter....After about 12-13 years, my production is down about 50%, so time to get a new one! The odd thing is it still produces less than 5PPM SFR!

Extra Low Pressure 4021 Commercial RO Membrane - $113.45

SpiroPure SP-XL4021 Extremely Low Pressure 4x21 Reverse Osmosis Membrane operates at extra low pressures for extra low energy consumption and savings.

www.allfilters.com

 

[Buckeye Hydro]

How about a 4021 membrane spec'ed at 80 psi? https://www.buckeyehydro.com/axeon-hf5-4021-ro-membrane-1-000-gpd/

 

[2Biz]

How about a 4021 membrane spec'ed at 80 psi? https://www.buckeyehydro.com/axeon-hf5-4021-ro-membrane-1-000-gpd/

You have my interest! Can you explain the "Why's" and the benefits of different membranes at different pressures? Does a membrane have to run at the advised inlet pressure? My system is set to run at 190 psi where Permeate and Concentration are supposed to flow about the same at .9 gpm....Its obvious I need to change the membrane as I'm about half that now even though PPM is still very low. But the incoming water is also cold since its winter which I understand lowers production. I just don't remember it being this low in the winter...To add, the incoming water is very soft (softened to 0 grains) to the RO system and reads about 110 ppm, so its also very low and maybe why the membrane has lasted this long?

 

[Buckeye Hydro]

You have my interest! Can you explain the "Why's" and the benefits of different membranes at different pressures? Does a membrane have to run at the advised inlet pressure? My system is set to run at 190 psi where Permeate and Concentration are supposed to flow about the same at .9 gpm....Its obvious I need to change the membrane as I'm about half that now even though PPM is still very low. But the incoming water is also cold since its winter which I understand lowers production. I just don't remember it being this low in the winter...To add, the incoming water is very soft (softened to 0 grains) to the RO system and reads about 110 ppm, so its also very low and maybe why the membrane has lasted this long?

Membranes are spec'd by the manufacturer at a certain pressure. This is the pressure at which they tested the membrane during design. So at 77F and x psi, the membrane will produce y gallons. So when users ask "How can I get faster production from my RO system?" one common answer is to add pressure - get a bigger pump or turn the pump pressure up. Most often people don't want to spend the $ on a new pump. So as an option we suggest to use a different membrane - use one that is spec'ed at a lower pressure. So the membranes we stock are spec'ed at 225 psi, or 150 psi, or 100 psi, or 80 psi. They are nominally the identical physical size, but they perform to spec at different pressures. Most users don't know that they can use a lower pressure membrane and get nearly identical quality water produced. Once you do know this... there's really no reason not to use a lower pressure membrane in most circumstances.

You have a 4" diameter membrane, so you really shouldn't run your concentrate less than 3 gpm. Except your system manufacturer may have undersized the pump to reduce the system cost. If I were you, I'd buy an 80 psi membrane, and increase your concentrate flow to 3 gpm.

Yes - soft feed water will lengthen the useable lifespan of a membrane, all other things being equal. <1 gpg feedwater is what is typically required/spec'd by RO system manufacturers.

Yes - feedwater colder than 77F will reduce permeate production. The colder it is, the more it will reduce permeate flow. We have customers who use a blending valve to warm the feedwater... but that approach is not w/o a drawback because heating the water obviously costs $. As a rule of thumb, for every degree F less than 77, a membrane will produce about 1.5% less permeate, if the pressure is held constant.

Russ

 

[2Biz]

Membranes are spec'd by the manufacturer at a certain pressure. This is the pressure at which they tested the membrane during design. So at 77F and x psi, the membrane will produce y gallons. So when users ask "How can I get faster production from my RO system?" one common answer is to add pressure - get a bigger pump or turn the pump pressure up. Most often people don't want to spend the $ on a new pump. So as an option we suggest to use a different membrane - use one that is spec'ed at a lower pressure. So the membranes we stock are spec'ed at 225 psi, or 150 psi, or 100 psi, or 80 psi. They are nominally the identical physical size, but they perform to spec at different pressures. Most users don't know that they can use a lower pressure membrane and get nearly identical quality water produced. Once you do know this... there's really no reason not to use a lower pressure membrane in most circumstances.

You have a 4" diameter membrane, so you really shouldn't run your concentrate less than 3 gpm. Except your system manufacturer may have undersized the pump to reduce the system cost. If I were you, I'd buy an 80 psi membrane, and increase your concentrate flow to 3 gpm.

Yes - soft feed water will lengthen the useable lifespan of a membrane, all other things being equal. <1 gpg feedwater is what is typically required/spec'd by RO system manufacturers.

Yes - feedwater colder than 77F will reduce permeate production. The colder it is, the more it will reduce permeate flow. We have customers who use a blending valve to warm the feedwater... but that approach is not w/o a drawback because heating the water obviously costs $. As a rule of thumb, for every degree F less than 77, a membrane will produce about 1.5% less permeate, if the pressure is held constant.

Russ

My procon pump or booster pump for production is a Fluid O Tech P0301V which is about 1.8gpm and has a built in regulator that I set pressure on the membrane to 180-190psi. Then I control Permeate and Concentration from another valve by changing the amount of concentrate or bypass...If I were to order the Axeon 80-100psi membrane, would I need to reset the pump pressure to 80-100 or would it automatically adjust based on the more free flowing filter? You can't build pressure if the Axeon is more free flowing..I hope that makes sense? I know you recommended a larger pump, just trying to make sense of it all....

 

[Buckeye Hydro]

Fluid O Tech makes good pumps.

So 1.8 GPM allows for 0.8 gpm permeate a 1.0 gpm concentrate. That's not enough concentrate with a 4" membrane.

You adjust the outlet pressure of the pump. You can run an HF5 (80 psi) membrane at much higher pressures. Running it at pressures higher than 80 will make it produce more than the spec 850 gpd. Max operating pressure is 400 psi.

Russ