RO/DI Help

[wrxreefer823]

Good morning fellow reefers!

So I have a quick question about how I should set up my RO/DI system. Our house has a water pressure booster pump, pictured below, which shuts itself off at 70 PSI and generally doesn’t drop below 60 when running. I’ve experimented and shut it off and ran a few faucets, and it looks as though once pressure runs out from the pump the whole house is around 20 PSI. So, I was going to tap into the pressurized side of the piping to feed an RO/DI, I’d be tapping in 7/8” PEX.



Now for the questions. There’s a local guy selling his RO that he’s done some minor upgrades to for $100.



I would need to get new filters and membrane for it which will set me back an additional 60-70 bucks, and the booster pump kit I want is another $150 so I’m looking at $320-$350 depending if I need anything else for it. I’ve seen a 200 GPD unit in Marine Depot for $460 that will have everything I could possibly need for it, is that the way to go and just be done with it? Also considering I’m getting 60-70 psi off the house pump, is a booster pump overkill? Thanks!


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[mcgyvr]

Originally Posted by wrxreefer823

and it looks as though once pressure runs out from the pump the whole house is around 20 PSI.

Need a little clarification here first..
Are you saying that the "turn on" setpoint is 20PSI and "turn off" setpoint is 70 PSI? So there are times when your water pressure is only 20PSI?

If so you need to either adjust the "turn on" point or add a booster pump..
Your pressure pump should be able to be set so that anytime pressure is below (for example) 50 PSI that it turns on.. so you never drop below 50..

If your water pressure never goes below 50-60 then you absolutely do not need a booster pump as the ROI at thatpoint is quite a long time..

Are you on a well or just in an area far from the water tower or something?

[mcgyvr]

and yes thats a decent deal on that system (maybe offer $80).. You don't need the 2 blue capped small horizontal canisters and may want to only run a single DI stage instead of the 2 that are there..
Looks like it may have an additional taste/odor horizontal on top of the RO membrane that was once for a drinking water setup.. (minus the pressure tank).. Likely don't need that either..

[wrxreefer823]

Sorry, no the 20 psi is basically just on the feed side that’s not pressurized. From what I can tell it kicks on at around 60 so it really never drops below that.


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[mcgyvr]

Originally Posted by wrxreefer823

Sorry, no the 20 psi is basically just on the feed side that’s not pressurized. From what I can tell it kicks on at around 60 so it really never drops below that.

Ok.. Thats better.. Then no you don't need a booster.. You already have one for the whole house and 60PSI is more than sufficient..
People really only need boosters when their source pressure is less than 40-50 PSI when running and don't want to or can't adjust the pressure regulator in their house or up their well pump setpoints....

[wrxreefer823]

Originally Posted by mcgyvr

Ok.. Thats better.. Then no you don't need a booster.. You already have one for the whole house and 60PSI is more than sufficient..
People really only need boosters when their source pressure is less than 40-50 PSI when running and don't want to or can't adjust the pressure regulator in their house or up their well pump setpoints....

Gotcha, thanks! I was really wanting to go with one that was a dual membrane setup so I’m still on the fence.


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[mcgyvr]

You could add another membrane to that unit easily..
https://airwaterice.com/membranes/ad...ur-system.html

[Opus123]

You never stated, are you a well or city water?

You should really plan your RO unit based on your water quality.

[wrxreefer823]

I actually just met up with the guy to get his RO unit, seems like it’ll be a good starting point and I can add more to fit my needs. I’m on city water.


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[mcgyvr]

City water supplies around us are quite clean and don't really require anything "special".. My source TDS is always 60-70ppm at most..
They aren't afraid to go heavy on the Chlorine,etc... at the plant though..

[wrxreefer823]

Originally Posted by mcgyvr

City water supplies around us are quite clean and don't really require anything "special".. My source TDS is always 60-70ppm at most..
They aren't afraid to go heavy on the Chlorine,etc... at the plant though..

I live like a mile away from the water plant in Zebulon. Maybe it’s not such a bad idea to use two carbon blocks lol


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[mcgyvr]

It seems that your source may (please check by requesting your water quality report for your specific water vendor) use Chloramines which do require a bit more treatment to protect the membrane.. You may want to go with a block more suited for Chloramines..

Mine uses Chlorine which a single carbon block does just fine against..

[wrxreefer823]

It looks like the universal carbon blocks that come with the BRS replacement kits are good for both, so I should be good with that. Just ordered a kit as well as a second membrane kit. Now all I have to do is set up a mixing station in my garage and I can start filling my brand new Reefer that’s been sitting dry since June!


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[tkeracer619]

With Chloramines you will NOT want to use the 2nd membrane kit. If they haven't shipped it yet, cancel that or return it.

Contact time is very important with chloramines, especially when you have high PH (raleigh does). With dual membranes you will likely burn through DI and have premature failure of the membranes since those small carbon blocks just won't have contact time with the increased flow rate and 70psi feed pressure. Definitely double up on the catalytic carbon blocks.

How much water are you planning on making? With dual membranes, you'll probably only make 200gal of RODI water and your carbon will be spent. With a single membrane you'll probably get around 500gal of RODI on a carbon block.

Catalytic carbon breaks the Chlorine/Ammonia bond and removes the chlorine component. The lower flow through the carbon block the longer the cartridge will last and chloramines will be broken down more.

With PH above 7.5 the remaining ammonia component is not removed by the membrane, it passes through, and must be dealt with by the cation component of your DI. You will want a cation heavy DI cartridge. The mixed bed BRS sells is resintech MBD30. It has a 50/50 cation/anion ratio. So it will not last very long since the cation will exhaust rapidly. It is a great resin for general use but for chloramines going with a cation heavy cart (spectrapure maxcap) or separate beds is best.

To check the condition of your carbon stages you will want to measure total chlorine in the waste water. To check the condition of your DI you will want to measure total ammonia in your DI water. Since the chloramines can make it through without being broken down, if that happens, free chlorine and ammonia test kits will not register.

Also, if you end up with significant breakthrough, since chloramines half life is weeks instead of hours like chlorine, the chlorine exposure limit clock will not stop. You end up with membrane life of about a year.

I recommend Hanna Checkers HI711 and HI700

If you are going to make a lot of water, there are better options than the standard 10" cartridges.

I could destroy some chargril right about now... born and raised in Raleigh.

[mcgyvr]

If the intention of the dual membranes is to lower the amount of waste (Membranes wired in Series) and not produce more faster then the flowrate through the prefilters will remain the same I believe with a dual or single..

[wrxreefer823]

Originally Posted by mcgyvr

If the intention of the dual membranes is to lower the amount of waste (Membranes wired in Series) and not produce more faster then the flowrate through the prefilters will remain the same I believe with a dual or single..

I figured as much.

[wrxreefer823]

So I ended up cancelling the BRS order and going local to Reef Keepers (a GREAT bunch of guys) and got all Spectrapure stuff. I went with a happy medium and got the 90 GPD membrane.


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[tkeracer619]

Did you get chlorplus carbon blocks?

[mcgyvr]

Originally Posted by wrxreefer823

So I ended up cancelling the BRS order and going local to Reef Keepers (a GREAT bunch of guys) and got all Spectrapure stuff. I went with a happy medium and got the 90 GPD membrane.

Don't let Bill talk your ear off..
It is a cool store but I don't like how they don't list coral prices and likely make them up based on their impressions of "whatever" about you..

And did you get the proper flow restrictors for that membrane?

[wrxreefer823]

Originally Posted by mcgyvr

Don't let Bill talk your ear off..

It is a cool store but I don't like how they don't list coral prices and likely make them up based on their impressions of "whatever" about you..



And did you get the proper flow restrictors for that membrane?

Lol Bill is a trip. I can’t get out of there without spending at least an hour talking to him and Patrick. Yeah I used to go to a store up in PA just like that, nothing was priced but damn they had some good coral.

I didn’t get the restrictive because they didn’t have any in stock. I need to get a 7/8” PEX to 1/4” hard line “T” to tap into my house water, so I’ll just order that stuff from BRS. Just need to source a couple of barrels, a pump, and some PVC for a mixing/storage station, and I can start mixing and filling!

Also yes I get the good carbon blocks.

[tkeracer619]

Originally Posted by mcgyvr

If the intention of the dual membranes is to lower the amount of waste (Membranes wired in Series) and not produce more faster then the flowrate through the prefilters will remain the same I believe with a dual or single..

As it was explained to me by a filmtec engineer, the series membranes act as a single twice as long membrane. If you cut the waste ratio to 2:1 the second membrane doesn’t have the proper flow rate to keep from fouling. So where most people assume you cut the waste in half because that would be what common sense tells us, the reality is the waste ratio should remain 4:1 (or whatever you run at) to keep the membranes in good condition. So 4:1 with double product water gives you double waste water and total flow through the units.

Most people run a tighter waste than that with duals, no big deal, bulk membranes are cheap. I’m running my series spectrapure 99% membranes at 4:1 and after around 5 years and over 10s of thousands of gallons of product, they still are performing at a combined 99.5% rejection rate. This has saved me a ton on DI Resin.

[tkeracer619]

Also, I prefer to use a needle valve as a flow restrictor. This lets you keep it dialed in regardless of your water pressure or temperature of the source water.

[mcgyvr]

Originally Posted by tkeracer619

As it was explained to me by a filmtec engineer, the series membranes act as a single twice as long membrane. If you cut the waste ratio to 2:1 the second membrane doesn’t have the proper flow rate to keep from fouling. So where most people assume you cut the waste in half because that would be what common sense tells us, the reality is the waste ratio should remain 4:1 (or whatever you run at) to keep the membranes in good condition. So 4:1 with double product water gives you double waste water and total flow through the units.

Most people run a tighter waste than that with duals, no big deal, bulk membranes are cheap. I’m running my series spectrapure 99% membranes at 4:1 and after around 5 years and over 10s of thousands of gallons of product, they still are performing at a combined 99.5% rejection rate. This has saved me a ton on DI Resin.

While I agree that running membranes in series may lead to a somewhat decreased lifespan I save the cost of multiple membranes each year just in the reduction in waste water... I'm on year 4 of my membranes and they are still going strong too..

[wrxreefer823]

That’s my thought process as well. However since I went with the 90 instead of the 75, I’ll see how that goes and maybe add a second if I see fit. The only reason I’m going single membrane for now is that the house pressure is right at the threshold of the requirement for a dual membrane setup. I’m going to pick up a couple of 70 gallon barrels tomorrow and then we’ll be out of town for the weekend. Hopefully I can get it all up and running this time next week!

[Opus123]

Originally Posted by mcgyvr

It seems that your source may (please check by requesting your water quality report for your specific water vendor) use Chloramines which do require a bit more treatment to protect the membrane.. You may want to go with a block more suited for Chloramines..

Mine uses Chlorine which a single carbon block does just fine against..

Chloramines will not hurt the membrane, at least not as quickly as chlorine. From what I read on the manufacturers website, it would take a lot of chloramines to damage a membrane.