Adding a second rodi membrane

Gtinnel · Oct 14, 2021

outhouse said:
I run a probe incoming, and a probe after 3rd membrane. You only need one booster pump. Trick is restricting waste water out of last membrane to tune product.

I just got home and was able to test my supply water, and it is120ppm, which I assume is easily good enough for an extra membrane, but with a feed pressure of 100psi would it be enough in your opinion for a third membrane?
Also do you have an adjustable restrictor, if not how do you fine tune the restriction.

outhouse · Oct 14, 2021

Gtinnel said:
I just got home and was able to test my supply water, and it is120ppm, which I assume is easily good enough for an extra membrane, but with a feed pressure of 100psi would it be enough in your opinion for a third membrane?
Also do you have an adjustable restrictor, if not how do you fine tune the restriction.

It's not the pressure. You have enough. Hook up that second membrane and see what Tds is coming out the 2nd membrane. That should determine if you can get away with 3

Gtinnel · Oct 14, 2021

outhouse said:
It's not the pressure. You have enough. Hook up that second membrane and see what Tds is coming out the 2nd membrane. That should determine if you can get away with 3

Ok I'll wait until I add a second membrane and then re-evaluate whether I can use or even want a third one.

outhouse · Oct 15, 2021

Gtinnel said:
Ok I'll wait until I add a second membrane and then re-evaluate whether I can use or even want a third one.

Id hate to advise a green light on 3, and have you only able to use 2. Only you can make that choice. How fast you use DI, is the determining factor. Having an output of 5 or 6 is one thing, having 10 or higher and your not going to be cost effective

Gtinnel · Oct 15, 2021

outhouse said:
Id hate to advise a green light on 3, and have you only able to use 2. Only you can make that choice. How fast you use DI, is the determining factor. Having an output of 5 or 6 is one thing, having 10 or higher and your not going to be cost effective

I understand it's hard to know if a third membrane would work for someone elses system that you don't anything about, except a brief description of. Ultimately if I decide to try it and it doesn't work out the cost of all of the parts is fairly insignificant. I appreciate the opinion from you and everyone else and understand ultimately it's on me to decide if I think it'll work. If not for you mentioning it I wouldn't have even realized that adding a third membrane is a possible option

Gtinnel · Oct 17, 2021

Yet again I reach out for you guys' collective knowledge. The second membrane kit from brs has a check valve build into the connector on the permeate side of the second membrane. I was going through the old parts that I have and mine does not have a check valve. Why is there a check valve there and is it needed? I actually do have a valve that would work, but it's metal and I'm not willing to use it.

outhouse · Oct 18, 2021

Yes you want the check valve. You dont want back pressure when shutting off booster pump, Its a one way flow deal

Gtinnel · Oct 23, 2021

So just to update I just installed my second membrane, I went with the water saver system from BRS. My pre di tds is still 1ppm, so it didn't go up even enough to go to 2ppm. The output volume is great (I suppose in theory double). I should've done this years ago.