Hey all so I looked and looked but I can't find anything so I'll ask. I have a 3 stage sediment filter going to 2 ro membranes before my so stages. I'm running a booster pump so psi is no problem but I want to get more water with less waste. So I was thinking about putting a 3rd membrane in series. The system was originally a 75gpd system now it's a 150gpd in theory it should become a 225gpd correct?
3 ro membrane
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Ron Reefman
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In theory, yes. Or you could just collect the reject water and run it through a 2nd time and potentially double your output?
So I pulled the trigger and got a 3rd membrane. So now I originally had a 75gpd system. But now with 2 water saver kits on it.. all I can say is it worked it now makes water very fast and it made 3.5gal of ro to 2gal of waste. Like I said couldn't find any info on this just thought I'd share
Ron Reefman
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Thanks for following up. I think this is a good idea, especially in areas where water is expensive.
JoshH
Tank Status: Wet...ish, growing things....
Are you saving money though if your RO membranes aren't performing at there best? You could be spending a ton more in DI resin than you otherwise would be and Resin is certainly more expensive than water... just something to think about..
Not trying to be a Debbie downer here or anything, I have definitely contemplated running a triple, even quad membrane setup as I have similar TDS that you do. I think this system works best when running with premium membranes to help avoid the situation I mentioned above
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JoshH
Tank Status: Wet...ish, growing things....
I currently only have a Dual membrane setup (Dual 90GPD membranes run in series) (I'm Not the OP) and have held off on purchasing a third strictly because of pressure loss and I'm not 100% sure you can run a booster between membranes. I haven't contacted anyone to see if this is okay to do or not but I THINK it would be just fine.
I have custom cut restrictors you order from Spectrapure and cut yourself, both are set to a 1:3 rejection rate.
My incoming TDS into the system is between 240-275 depending on the time of year. I join the product lines together right after the membranes so I'm not sure on the exact numbers from each individual one however both of them produce 0-1 TDS together. A third membrane MIGHT bump it to 1-2 TDS but once again without doing it I don't know for sure.
Okay answers:
-No I'm only using 1 flow restrictor rated for the first 75gpd membrane
- the tds out of the 1st membrane is 4
- the tds out of the 2nd membrane is 6
- the tds out of the 3rd membrane is 6
So I'm not burning through resin. If you figure that they're all so close to the first membrane I'm running a average of 5.3 tds to the di resin..
-yes there is a pressure loss after the first membrane I do have a booster pump
I know it sounds crazy and yeah my 3rd membrane is gonna die faster but it was a risk I took due to nobody on the internet posting they tried it I figured what the heck I'll try and post the results.
When I watched the brs video about the water saver kit they touched that a 3rd would or could be better but they never tried to my knowledge ( not saying they're right ) but it turns out they are.
-No I'm only using 1 flow restrictor rated for the first 75gpd membrane
- the tds out of the 1st membrane is 4
- the tds out of the 2nd membrane is 6
- the tds out of the 3rd membrane is 6
So I'm not burning through resin. If you figure that they're all so close to the first membrane I'm running a average of 5.3 tds to the di resin..
-yes there is a pressure loss after the first membrane I do have a booster pump
I know it sounds crazy and yeah my 3rd membrane is gonna die faster but it was a risk I took due to nobody on the internet posting they tried it I figured what the heck I'll try and post the results.
When I watched the brs video about the water saver kit they touched that a 3rd would or could be better but they never tried to my knowledge ( not saying they're right ) but it turns out they are.
Brandon Smith
AquaticArsenal.com
Your TDS coming out of the membranes seems really low. What is the TDS of your tap water?
JoshH
Tank Status: Wet...ish, growing things....
I was going to say the opposite, a typical high quality membrane should be maintaining a 99+ % rejection rate. And with an incoming TDS of 240 they are barely over 96% ...
@01xp this is what im referring to when I say you're chewing up resin. And to be fair, this could just be that you're running standard membranes and not premium ones. But it could also be the fact that your other membranes aren't recieving enough pressure to perform up to snuff. Once again I'm not trying to turn people off to the idea, just bringing up points on the 3 membrane experiment as like you said, no one else it seems has done it before... I think it's great and gives people a base set of numbers to go off of if they want to try it themselves
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This place in the UK sells a 3 - 150 gpd membrane system. So I t does work.
www.osmotics.co.uk
6 Stage 450 Gallon Per Day Reverse Osmosis System
Produce up to 1710 litres per day of Pure water for virtually any application with this 5-Stage RO System. Features high capacity 10” Sediment and Carbon Filters Rejects up to 99.8% of water born contaminants, bacteria and viruses (See Technical Specs tab) Unique recycling configuration, reduce...
www.osmotics.co.uk
Kazumi
Active Member
This place in the UK sells a 3 - 150 gpd membrane system. So I t does work.
6 Stage 450 Gallon Per Day Reverse Osmosis System
Produce up to 1710 litres per day of Pure water for virtually any application with this 5-Stage RO System. Features high capacity 10” Sediment and Carbon Filters Rejects up to 99.8% of water born contaminants, bacteria and viruses (See Technical Specs tab) Unique recycling configuration, reduce...
It appears that those membranes are plumbed in parallel, that way they way can get to 450 gal/day.
Just to add some more fuel to the fire... if you look up https://puromax.com/commercial-industria-water-filtration-reverse-osmosis-systems
Yes I know that it's commercial grade stuff but all I did was implement the same concept on a smaller scale
Yes I know that it's commercial grade stuff but all I did was implement the same concept on a smaller scale
So here we go I did a water change tonight and thought I'll show what's going on with pics and a video. Here's the setup again originally a 75gpd system with 2 water saver kits on that house 75gpd membrane. I'm running a booster pump at about 83psi with dual di canister.
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