RO/DI Unit Questions

[ILIKECOUGARS]

Hi,
I just pick up a new 75 GPD RO/DI unit, when I was in Calgary last month, and was wondering whats the ratio of the waste to good water should be? I just connected it up and it seems to produce a lot more waste water than good, is there a break in period for the RO membrane?
Thanks,
Ed.

[xtreme]

It is normal to produce more waste water than good. I think the ratio is like 3 or 4:1

[mark]

3-4:1, ro's aren't the greenest

[PoonTang]

pressure and temperature of the infeed water play a big part too, but normal is about 4:1

[ILIKECOUGARS]

Yea, I kind of thought that. Looking like it's about 3.5 to 1 right now. I quess it would be a matter of time, a few W/C to see a differents it would make. I had always use tap water.
Ed.

[Funky_Fish14]

A booster pump will very much alter or change your ratios. I have two 50gph membranes hooked up in series, with a booster pump running before them... and im getting at least 2:1 waste to good water, or better. Even with COLD water going in.

[Werbo]

Could you provide the specifics of this "booster" pump that you are using?
Make, model, where you bought it, ect.
Thanks,
Tyler

[Adam NS.]

3-4:1, ro's aren't the greenest

They are if you plumb them to water the garden with your waste water.

[fkshiu]

They are if you plumb them to water the garden with your waste water.

Or use it for your washing machine.

[Adam NS.]

Or use it for your washing machine.

????????? please xplain

Adam

[fkshiu]

????????? please xplain

Adam

Use the waste water to wash your clothes. That RO waste water is cleaner than what comes out of your tap since it has already gone through sediment and carbon filters.

[StirCrazy]

A booster pump will very much alter or change your ratios. I have two 50gph membranes hooked up in series, with a booster pump running before them... and im getting at least 2:1 waste to good water, or better. Even with COLD water going in.

the 2:1 is nothing to do with the booster pump, but rather because you are running it in series, so you are taking the 4:1 output and sending it to a second filter which takes the 4 waist water and does a 4:1 on it again.. so you are probably realy about a 2.5 to 3:1 total. this is fine if you have very soft water, but it will kill your second membrain faster if you have hard water.

I use a booster pump on my dual set up as I only have 40psi out of my tap and I am running dual 160gpd membrains, but I run them in parallel so I am sending tap water to both membrains and I adjust my overall ouput to 4:1 and I do a 4 min back flush once a week.

a booster pump will just allow you to run at a high PSI which will give you a higher output. dow style membrains (which are most of the ones in our hobby) realy have two ratings one at 60PSI and one at 90 the question is which one is being used when you buy your replacment membrains.

I use 100/160 dow membrains, but you can get 50/75 and other sizes.. so you might go to one store and a company has relabled it as a 50gpd, and another company may relable it is a 75gpd.. problem is they don't tell you which PSI so one guy will go home and run 90 PSI and get 75 out of his 50GPD membrain where the other guy goes home and only gets 50GPD at 60 PSI out of his 75GPD membrain.

So unless I can see the original DOW lable I don't buy them from that shop because I don't want to go to buy a 100 GPD and end up with a 75/90 which they are selling as a 100 as it is close enough at 90 PSI.

Also one of the best things you can do is buy an extra filter housing and run two Carbon block filters after your main sediment filter.. I bought a big blue and run a 25 to 1 absolut gradiated filter in it. the big blue is a 10" tall filter like the normaly ones but it is 6" diamiter, like you see on home filtration systems. this allowed me to remove the standard sediment and replace it with a second carbon block.

the reason for this is Chlorine will kill a membrain in no time. on a low flow set up you will get most of it out with a single carbon block, but if you go higher flow or PSI you may not be getting it all out and then have to wonder why TDS is creaping up after a short while.

Steve