Dual RO/Membrane System

[dwall174]

What are the pro's & con's of running dual ro/membranes in series versus parallel.
Obviously there's more parts needed for a parallel system, But are there any other advantages or disadvantages.

[roclement]

If you take the waste line from one mebrane and run it thorugh a second membrane (in-line)you minimize waste water, it is a sure fire way to maximize water production and minimize waste but the problem is that you need a decent amount of water pressure to achieve this so the unit needs to have a booster pump.

From my research, and my conversation with Jim from "The Filter Guyz", the best membranes to do is are the DOWN 100gal per day. Many companies sell in-line kits to upgrade your unit.

Running paralel only increases production, but doesn't affect waste loss, you'd also need a booster pump in order to push water through the two membranes.

Hope this helps!

Rod

[dvc_r]

I have a Coralife Pure-Flo 50 gpd 3-stage. I was going to run two in parallel to double my output but I found out that the 100 gpd cartrige fits in the same housing! So why bother to go through the trouble of running two? The key is to change the small plastic fitting that fits into the 1/4 inch tubing.

[roclement]

I have a Coralife Pure-Flo 50 gpd 3-stage. I was going to run two in parallel to double my output but I found out that the 100 gpd cartrige fits in the same housing! So why bother to go through the trouble of running two? The key is to change the small plastic fitting that fits into the 1/4 inch tubing.

running two in-line lessens the waste water to almost nothing...

rod

[dwall174]

the problem is that you need a decent amount of water pressure to achieve this so the unit needs to have a booster pump.

I have around 75~85 PSI water pressure, so I'm hoping I will be fine without a booster pump.

My biggest problem is low out-put in the colder months here in Michigan. My incoming water temperature can get as low as 45 degrees here in the winter! With water that cold the out-put of my 75 GPD membrane is only around 40 GPD & the waste to pure ratio goes from (4 to 1) to (6 to 1)

[dvc_r]

the waste to pure ratio goes from (4 to 1) to (6 to 1)

4/6 to 1: that's crazy!

I'm still green with most this stuff (2 yrs w/fish & 1 year using RO filters) but I can't see how you can run a second filter (in series) since the water just trickles out. Even with a pump I don't think there's enough volume of water to use a pump.

I know someone that breeds Discus and works with commercial water filtration systems he also designs and patents filtration systems. Beleive it or not he even came from Michican.

If you want I can get more info for you. If so, are there any other questions you may want to ask before I write him?

[Ed13]

If you take the waste line from one mebrane and run it thorugh a second membrane (in-line)you minimize waste water, it is a sure fire way to maximize water production and minimize waste but the problem is that you need a decent amount of water pressure to achieve this so the unit needs to have a booster pump.

From my research, and my conversation with Jim from "The Filter Guyz", the best membranes to do is are the DOWN 100gal per day. Many companies sell in-line kits to upgrade your unit.

Running paralel only increases production, but doesn't affect waste loss, you'd also need a booster pump in order to push water through the two membranes.

Hope this helps!

Rod

Great explanation Rod!

For ease I explain it like this.
Basically:
In-line: Increase of product water/waste water. Or 2 product water outputs and one waste water output. You are running the waste water from the first membrane through the second.

Parallel- More production at the same ratio. Or 2 product water outputs and 2 waste water outputs.

Either way you'll need high PSI number at the input and appropiate restrictors.

The second membrane in line should be replace more often and the DI resin if used too.

You prob know this, but RO systems really work best at 60 PSi( no more than 100 though), 77F temp, <250 TDS and at a 4:1 ratio. The closer to these numbers you can get the better, whether you run 1 or 2 membranes in series or parallel