RODI Question, Possible CO2

brclark82 · Feb 21, 2023

I have the BRS 7 stage RODI unit. I have 450 tds going in, 2-3 after RO and 0 final. This is great except I am burning through anion resin at a very high rate.
Like probably 100-150 gallons per refill.

I have come to the conclusion that this is most likely due to high CO2. I do not want to build one of the CO2 PVC degassers I've seen here because of possible overflow issues plus vertical space restraints for the gravity fed DI part.

My plan is to just use 2 Brute cans and fill one with tap water, de-gas for 24 hours or whatever it takes. Then pump through my RODI unit into another Brute can.

2 questions

1) Are there really any other options to why I'm burning through resin this quickly or a way to test this before I try my plan?

2) What kind of pump would be best to use in this case? I would like it to be able to shutoff automatically when the trash can is empty, I was thinking sump pump? Or is there a better option?

Thanks

Saltyreef · Feb 21, 2023

brclark82 said:
I have the BRS 7 stage RODI unit. I have 450 tds going in, 2-3 after RO and 0 final. This is great except I am burning through anion resin at a very high rate.
Like probably 100-150 gallons per refill.

I have come to the conclusion that this is most likely due to high CO2. I do not want to build one of the CO2 PVC degassers I've seen here because of possible overflow issues plus vertical space restraints for the gravity fed DI part.

My plan is to just use 2 Brute cans and fill one with tap water, de-gas for 24 hours or whatever it takes. Then pump through my RODI unit into another Brute can.

2 questions

1) Are there really any other options to why I'm burning through resin this quickly or a way to test this before I try my plan?

2) What kind of pump would be best to use in this case? I would like it to be able to shutoff automatically when the trash can is empty, I was thinking sump pump? Or is there a better option?

Thanks

You can be sure by buying a water co2 test kit.

The only flaw i see with your idea is you will be only producing a small amount of product water with a 20-40g brute full of tap water and will need a very strong booster to build enough pressure to reliably feed your membrane.

Buy a 3 way DI bypass valve from spectrapure.
Blast all your RO into the brute can after its produced and then airate.
use a small pump (mj1200) connected with a 1/2" to 1/4" diy quick connect fitting and attach to your 3 way valve where normally your RO output is connected and switch the valve position, turn on pump and pump airated RO water nicely through your resins.

It simplifies things to only needing small pumps since you already have decent water pressure and you can make a whole heck of a lot more water at a time than your idea.

You can get a float that will shut off the water pressure when the brutes are full too.

brclark82 · Feb 21, 2023

Saltyreef said:
You can be sure by buying a water co2 test kit.

The only flaw i see with your idea is you will be only producing a small amount of product water with a 20-40g brute full of tap water and will need a very strong booster to build enough pressure to reliably feed your membrane.

Buy a 3 way DI bypass valve from spectrapure.
Blast all your RO into the brute can after its produced and then airate.
use a small pump (mj1200) connected with a 1/2" to 1/4" diy quick connect fitting and attach to your 3 way valve where normally your RO output is connected and switch the valve position, turn on pump and pump airated RO water nicely through your resins.

It simplifies things to only needing small pumps since you already have decent water pressure and you can make a whole heck of a lot more water at a time than your idea.

You can get a float that will shut off the water pressure when the brutes are full too.

You know I didn't even think about the ratio of waste water, thanks.

What would be the purpose of the 3 way valve instead of just having the pump tubing connected directly to the di canisters?

KStatefan · Feb 21, 2023

I use a CO2 degassing chamber but do not gravity feed my DI. The DI water gaviity flows in to a 5 gallon container then I have a tunze pump on a high-low tank controller to pump thru my DI resin.

Saltyreef · Feb 21, 2023

brclark82 said:
You know I didn't even think about the ratio of waste water, thanks.

What would be the purpose of the 3 way valve instead of just having the pump tubing connected directly to the di canisters?

Nothing but ease of use.

My fat fingers cant reach behind the canisters on my 5 stage since its all on one hanger so i split the line on top with the 3 way valve and have the one dedicated RO line running to my brute RO bin to airate.

Now just have to pop off the RO inlet tubing from my membrane to the valve, plug in the tubing from my mj1200 pump and switch the position to flow airated RO through my canisters.

If you have room to reach all the fittings you can simply just unplug and reroute.

brclark82 · Feb 21, 2023

@Saltyreef do you have anything to keep the pump from running dry or do you just keep an eye on it and turn it off?

Saltyreef · Feb 21, 2023

brclark82 said:
@Saltyreef do you have anything to keep the pump from running dry or do you just keep an eye on it and turn it off?

I time my fills as im filling 5g jugs from the brute.
Takes about an hour per 5g.
In the event i forget, my MJ1200 fails to pump but stays wet since its just gulping air and water from the bottom so no damage has come yet.

I havent had to use one of these yet but it would work great to shut off the pump before the water runs dry.

https://a.co/d/bAFl4u9

For my RO bin i have a ASV float for my membrane.

brclark82 · Feb 21, 2023

@Saltyreef could you possibly point me in the right direction (link possibly) for the adapter I need to connect the mj1200 to my 1/4” rodi water line…I can quite tell what kind of connection it has or what would work

Saltyreef · Feb 21, 2023

brclark82 said:
@Saltyreef could you possibly point me in the right direction (link possibly) for the adapter I need to connect the mj1200 to my 1/4” rodi water line…I can quite tell what kind of connection it has or what would work

Yes indeed. Its a 1/2" x 1/4" push to connect adapter. They sell them on amazon but i couldnt find any that i was comfortable leaving inside the RO bucket long term. IIRC even the john guest ones have a small metal collar inside but i havent had them corrode on me yet.

Heres a link to a thread i replied to that has the links to individual pieces to screw together you can pick up at a local lowes or HD.

https://www.reef2reef.com/threads/pump-water-through-rodi-system-without-faucet.963257/post-11013109

brclark82 · Feb 21, 2023

Saltyreef said:
Yes indeed. Its a 1/2" x 1/4" push to connect adapter. They sell them on amazon but i couldnt find any that i was comfortable leaving inside the RO bucket long term. IIRC even the john guest ones have a small metal collar inside but i havent had them corrode on me yet.

Heres a link to a thread i replied to that has the links to individual pieces to screw together you can pick up at a local lowes or HD.

https://www.reef2reef.com/threads/pump-water-through-rodi-system-without-faucet.963257/post-11013109

awesome, this is exactly what I needed.

also i understand better why you use the 3 way valve from that post too

thanks for your help I am going to try and get this setup