PDA

View Full Version : 3 X RO membranes.


outy
12/20/2017, 09:08 PM
Yes you can

Decided I would give it a try. Ones water TDS will dictate how many membranes one can run.

Stats are as such, incoming TDS 29 tonight, usually 27. Outgoing TDS 0 before the BRS nuclear grade resin.

She is not pretty, but functions perfect in a 120 year old house basement. The plumbing is rusty with galvanized pipes, you can see the color of the semi new prefilter already turning rust colored. Even the first carbon block is already changing color. I will have to swap them out shortly, never let the third change color.

https://s14.postimg.org/va90ivlap/20171220_183332.jpg

boxfishpooalot
12/21/2017, 09:44 AM
What does this do than just having 1?

mcgyvr
12/21/2017, 09:52 AM
Its one method to change the rejection rate..
So with one you may waste 4 gallons to get 1 good gallon of water..
With multiple membranes you may now waste only 2 gallons to get 1 good gallon of water..

outy
12/21/2017, 11:45 AM
What does this do than just having 1?

My rejection rate is almost the same as production rate.

using 75gpd membranes, I can now make 225G in a 24 hour period.

I do 100G water changes every few weeks to a month right now, its nice to fill the tank quickly.

lately I have my ATO in a 30 minute timer, and excess goes to mixing tank, so I don't have to touch anything and I have a 100G of ro water in a week.

Just redid plumbing so I also have 10 minute 100g water changes done start to finish in about 9 minutes.

Whole point of my multiple membrane usage is to take advantage of the extremely good water I'm using.

Rover88
12/21/2017, 01:50 PM
This confuses me.

So you have the waste... And the clean... From the first, going to the 2nd? And waste/clean from the 2nd, going to third? And then from the third, you dump the waste?

Haksar
12/21/2017, 01:57 PM
My rejection rate is almost the same as production rate.

using 75gpd membranes, I can now make 225G in a 24 hour period.

I do 100G water changes every few weeks to a month right now, its nice to fill the tank quickly.

lately I have my ATO in a 30 minute timer, and excess goes to mixing tank, so I don't have to touch anything and I have a 100G of ro water in a week.

Just redid plumbing so I also have 10 minute 100g water changes done start to finish in about 9 minutes.

Whole point of my multiple membrane usage is to take advantage of the extremely good water I'm using.

I am currently using a membrane rated for 100GPD with one motor and
want to increase to 150GPD by splitting the membrane to
75GPD each . It’s a four stage RO/ DI unit . Is it possible
I can do this without adding additional motor and is there any use
doing it other than wasting money .

outy
12/21/2017, 03:05 PM
This confuses me.

So you have the waste... And the clean... From the first, going to the 2nd? And waste/clean from the 2nd, going to third? And then from the third, you dump the waste?


Good 0 TDS water comes out all 3 membranes and is fed straight to DI

waste from 1rst feeds 2nd membrane and that waste feeds 3rd.


With each membrane the waste gets higher and higher TDS

outy
12/21/2017, 03:12 PM
I is there any use
doing it other than wasting money .

Not wasting money if your saving water.

Its all about saving water.

Is it possible
I can do this without adding additional motor

You see I only have 1 motor.

So yes no more motors needed.

All you need is a T fitting to plumb in second membrane clean water output.

and
want to increase to 150GPD by splitting the membrane to
75GPD each

Easy, just add second membrane.

Your incoming TDS has to be low or its not recommended.

The trick here is measuring the output of second membrane, if the TDS is low your OK, if the TDS is not low you will chew through DI resin.


with each added membrane that is fed waste water, the incoming TDS is also raised. So if you have TDS of 100 incoming to first membrane, your second membrane may be getting 150TDS.

zachfishman
12/21/2017, 08:20 PM
Incoming TDS is 29?! At that point I’d almost consider simply running some very large DI canisters and regenerating the resin occasionally - zero water waste.

rocsec1
12/21/2017, 08:42 PM
I use two ro mebmbranes and am getting much better production. I am planning to add a second di canister soon.

outy
12/21/2017, 10:51 PM
I use two ro mebmbranes and am getting much better production. I am planning to add a second di canister soon.

Just remember to keep the DI canisters up and down, not on their sides.

outy
12/21/2017, 10:54 PM
Incoming TDS is 29?! At that point I’d almost consider simply running some very large DI canisters and regenerating the resin occasionally - zero water waste.

Id feel guilty with no membranes lol

I am lucky but it comes at a price, something in the water induces GHA with every water change. for 25 years when I change water I will get algae for a while. So I often go a year without changes.

Changing my ways though. Now using more DI and nuclear grade, I'm seeing if I can beat this curse. So far so good.

Rover88
12/22/2017, 08:47 AM
Good 0 TDS water comes out all 3 membranes and is fed straight to DI

waste from 1rst feeds 2nd membrane and that waste feeds 3rd.


With each membrane the waste gets higher and higher TDS

OH THAT MAKES SENSE.

I've got two RO units at home, but I've only got one hooked up. I might have to try this!

outy
12/22/2017, 11:10 AM
OH THAT MAKES SENSE.

I've got two RO units at home, but I've only got one hooked up. I might have to try this!

As long as your TDS is acceptable leaving second membrane, your good to go