RO/DI unit pressure

[Jack]

I was reading something about this on one of your other posts, I just wanted to ask what PSI my Reefpure 50gpd Tornado unit should be run at? I could go to 80psi if I wanted to, but Im running it @ around 50-60psi to be safe. It says it needs to be at least 37psi to opperate. Thanks for any input!

[Seaquest]

Hi Jack

37 is fine, to high a pressure will damage the membrane, as it is only able to pass fluid a certain rate.

Cheers

[naesco]

There is a 'pressure regulator' in the plastic hose just before the input to the first 'canister'.
It does not make any difference if you are operating off a house hose bib. The tap should be fully turned on.

[Jack]

Ok, good to know. But I did run it at 80 PSI once. You don't think I damaged the membrane, do you?

[Acro]

http://www.canreef.com/ubb6/cgi-bin/ultimatebb.cgi?ubb=get_topic;f=28;t=000001

[StirCrazy]

most domestic RO units have a max of 125psi on the membraine so i don't think your 80 psi hurt it at all Jack.. does it still make good water?

steve

[Acro]

Steve,

Please define domestic?

[StirCrazy]

The R/O's being sold by kent, reefpur ect.. are all based off a domestic membraine. the intended use is for drinking water in your home. this is oposed to comercial models (like the kind we use on the ships) that make 230gph of ultra pure water. the main differnce being that a domestic unit will run off of standard house hold water pressures 40 to 80 psi. acording to AMI, there resadentual membrains are recomended to be operated at
Maximum Operating Pressure 125 psi (0.86 MPa)
Maximum Feed Flow Rate 2 gpm
Maximum Operating Temperature 113°F (45°C)

whare the RECOMMENDED OPERATION CONDITIONS for there comercial thin film membraine are
maximum operation pressure 300 psi
maximum feed flow rate - 2" elements: 3 gpm
2.5" elements: 6 gpm
4" elements: 17 gpm
maximum operating temperature 113° F (45° C)

this is the filmtec/dow specs for resadentual thin film membrains (probably the most commen one)
Operating Limits
Maximum Operating Pressure 125 psi (0.86 MPa)
Maximum Feed Flow rate 2 gpm (7.5 lpm)
Minimum Concentrate Flow Rate 4 x permeate flow

there comercial model like the ASI is a 300psi one. another thing that seams commen is domestic tap water membrains seam to be 98% rejection, whare the comercial ones are mostly 99%

if you want to see the kind I work with on a daily basis HERE (http://www.appliedmembranes.com/filmsea.htm) is a link to the specs.. I am curently working at setting up a fully working trainer at the school (when i go back to work that is) so I will be able to make about a ton of water / hour with a 99.6% rejection rate.

I hope this answered yyour question Jamie

Steve

[Acro]

Steve,

yes that helps. Thanks. I am ignorent on this subject. Any and all factual info is appretiated.I have been having some good talks with fellow hobbiest about the quality of different ro membranes.We all seem to go for cheap as possibable in this hobby. With so many different ro membrane I wonder if we sacrifice quality. One freind has perchased a different ro membrane then he ran prior. Now he seems to go though di resins big time. All the different membranes seem to carry different price tags and I would assume different quality. I wonder what the best domestic ro membrane is and whats second and so on.?

Jamie

[StirCrazy]

I would hazzerd to guess that all "domestic" mebrains arre pretty close to each other in terms of quality and preformance. I found a link to a good place to buy replacement membraines on a post on RC so here it is
Replacment membraines (http://www.wateranywhere.com/Virtual/VirtualPages/Item_Page_MERCHANT_6.asp?ItemCode=FILMTECRES&Item_Process_Mode=ADD)

hmm I need a spell checl program for this LOL

Steve

[Jack]

I think we all need spell check ;)

Thanks guys, good to know I didn't hurt my brand new RO membrane, boy would that of made me mad.

Steve, thanks for the info. And to your question about does it make good water? Uhh, yeah. Sure I don't know. I have no major problems yet, I just have a bit of algae cause the tank is new, you can barely notice it though. Snails and hermits are comming tommorow :D

[Marianne]

Yes, your membrane is fine, actually if you run it at 80 PSI you will get better production and less wastewater.

35 PSI is dead minimum to get reverse osmosis to work. Be low that all the water will go to drain, you can not overcome the pressure to permeate the membrane.

Jamie posted a link to another post that covers it quite well.

My experience of using thousands of membranes (low pressure residential) is they are not all the same. Dow Filmtec has consistently preformed. More times than not, better than the specs. Desal by Osmonics membranes has brought me great heartache, with bad batches and apparently not so good quality control.

I do have the advantage of feed back form thousands of users. And believe me when something goes wrong I HEAR ABOUT IT!!! So for me to keep people happy and lessen problems (and problem calls) I use Dow Filmtec.

[Acro]

Marianne,

Your knowledge is a great asset to this board thank you.

Jamie

[Davesreefpure]

You need 37 psi to permeate the membrane you will have an increase in waste and gpd the desal membranes are rated at 90 psi and the filmtec are rated at 80 I woud not stay at 80 but close is nice also the 125 psi people are talking about is the canasters and membrane housing you hit the membrane at 125 you will tear the thin film.

P. s. MARIANNE IS THE WATER God BUT HAD TO ATLEAST PUT IN MY 2 CENTS
Hope I do not up[set here cause she can make me look foolish in her sleep lol