Quick RODI unit questions

kyley

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Hi All,
I just wanted to sanity check my TDS readings and see if my DI Resin chamber is working right...
I have one TDS probe that I move around, and I see that it reads:
245 TDS from the faucet
225-290 Waste water range
18 TDS on the input to the DI Resin. Do those numbers all sound about normal? Consider that I have brand new sediment, 1 micron carbon block, and catalytic carbon before it. Dual membranes were replaced in the past year.

Then on the output of the DI Resin (last stage), I'm reading 10-11 TDS. Shouldn't that be zero? The DI Resin still looks dark blue to me - not brown at all... But it's weird, because it never fills up with water as you can see below. Is that normal?

And last issue, I just replaced the carbon blocks because I realized I have ammonia in my water, apparently from chloramines. It tested at 1.2ppm with the more reliable Red Sea ammonia test kit. However, I'm *still* getting an ammonia reading! 0.4ppm. 1/3 of the previous amount, but I shouldn't have ammonia! I now have a 1 micron carbon block and catalytic carbon as well. Thanks,
--Kyle
IMG_20200111_151912.jpg
 
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Quietman

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So the 18 out of the RO portion is a tad high even running dual in series...but not disgustingly so. 5% rejection is limit and your about 6 above that but you will have higher TDS out in that configuration.

Do you know house water pressure? Low pressure can impact membrane efficiency - 50# for one membrane is recommended and 65# for dual.

It's really hard for the water NOT to flow through the resin with the bottom fed BRS canisters. If you have water coming out, going to be going through resin, but check the inner canister just in case.

Could have impurities not easily removed with dual mixed media. I did. Had to go to three stage DI (Cation/Anion/Mixed). I would start out with fresh media and after just 20 or so gallons have measurable TDS on output. Haven't since, but I burn through anion resin in just a few hundred gallons.

So first thing...I'd check the water pressure. Going to effect everything. Recheck all your seats/orings and that your packing media tightly. Might want to try different media combinations before spending money on more canisters (you can stack cation/anion in one and mixed in other).
 

Saltyreef

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245 into the unit, 18 out of the membrane. I haven't measured after the sediment and carbon stages before the membrane if that's what you're asking?
No i was trying to figure out your rejection rate of membrane. Youre at 92% which is fine.
If youre running two stage DI, you might want to look into spectrapures maxcap cartridge and silica buster. Im at 200+ gallons and havent even exhausted my 1st stage. And my incoming tds is 350. Whats your rejection ratio? Have you measured it?
 
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kyley

kyley

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So first thing...I'd check the water pressure. Going to effect everything. Recheck all your seats/orings and that your packing media tightly. Might want to try different media combinations before spending money on more canisters (you can stack cation/anion in one and mixed in other).
I don't know on water pressure. My pressure guage quit working for some reason, but I think it's pretty high here.

I'm so disgusted right now that I can't get a simple RODI until to work properly. I added to my OP that I was measuring 1.2ppm ammonia out of my RODI unit. I just replaced the carbon filters and I'm seeing 0.4ppm ammonia even after adding catalytic carbon instead of just two carbon blocks. So I have TDS, ammonia, and now I'm not even sure if my RODI unit is configured properly with so many valves after I added the 2nd membrane years ago. I'm going to draw a diagram of the flow to make sure it's correct. Thanks,
--Kyle
 
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kyley

kyley

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No i was trying to figure out your rejection rate of membrane. Youre at 92% which is fine.
If youre running two stage DI, you might want to look into spectrapures maxcap cartridge and silica buster. Im at 200+ gallons and havent even exhausted my 1st stage. And my incoming tds is 350. Whats your rejection ratio? Have you measured it?
I don't know what rejection ratio is. Did you just say it's 92% based on (245-18)/245?
--Kyle
 

Saltyreef

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I meant to say your product to waste water ratio. If not properly set, your DI will exhaust too quickly or youll output will be a lot slower than normal.
Basically you measure how many ML disxharge from your DI output and your waste water.
Divide the DI by the waste output and youll recieve your ratio....needs to be at 5 max. The less it is, the faster youll be making water and exhausting filters.

A quality RODI unit goes a long way.
You shouldnt be measuring any kind of toxicity after your carbon block. If you do....its not working.

Again i have really good experiences with spectrapure. I bought the maxcap standard and it was pretty plug and play right out of the box.

Directions are cut and dry, their products knock the socks off everyone elses to be honest.
And their customer service is amazing.
 

Quietman

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So...can I guess? You probably have high pH water from tap.

If so, then that ammonia is going to be gaseous and not charged, which means it's not going to be removed through mixed media. This I think was me...I have very high pH city water >8.5 and chloramines.

The solution could be three stage DI (the first drops the pH changing the ammonia).

More here...see if this could be you. If so, I would just buy the anion and cation and put them in the first canister - cation first, then anion on top. If your ammonia drops to 0..bingo!

https://www.reef2reef.com/threads/d...a-from-chloramines-brstv-investigates.420964/
 

theMeat

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Would suspect water pressure is low or wrong size flow restrictor for your membrane,
What size flow restrictor and how many gpd membrane?
 
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kyley

kyley

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I meant to say your product to waste water ratio. If not properly set, your DI will exhaust too quickly or youll output will be a lot slower than normal.
Basically you measure how many ML disxharge from your DI output and your waste water.
Divide the DI by the waste output and youll recieve your ratio....needs to be at 5 max. The less it is, the faster youll be making water and exhausting filters.

A quality RODI unit goes a long way.
You shouldnt be measuring any kind of toxicity after your carbon block. If you do....its not working.

Again i have really good experiences with spectrapure. I bought the maxcap standard and it was pretty plug and play right out of the box.

Directions are cut and dry, their products knock the socks off everyone elses to be honest.
And their customer service is amazing.
Okay, I confirmed that my pressure guage just doesn't work. Hooked it up directly to the faucet and it didn't move.

In 60 seconds, I made about 435 mL of RODI water and about 460 mL of waste water, so it's 0.95. I'm confused by how you phrased your note above though. Is this appropriate or no?

I hate the idea of spending even more money here, but I'll take a look at the unit you're suggesting. Can you send me a link to the specific one? Keep in mind, I have to deal with chloramines in my water. :-( Thanks,
--Kyle
 
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kyley

kyley

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So...can I guess? You probably have high pH water from tap.

The solution could be three stage DI (the first drops the pH changing the ammonia).
Not sure. I have a pH probe on my Apex but not a stand alone one. I tested with API High Range PH since that's all I have available and it shows 7.4 (or less), but that might only work with saltwater?
 
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kyley

kyley

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Would suspect water pressure is low or wrong size flow restrictor for your membrane,
What size flow restrictor and how many gpd membrane?
No idea. It's the one that came with the RODI unit, but then I got the upgrade to dual membranes... Thanks,
--Kyle
 

theMeat

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While dual membrane unit can save water they can be more trouble than worth. Especially if water pressure is low.
Guessing you have 2- 75 gpd membranes. Most common.
City water?
 
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kyley

kyley

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While dual membrane unit can save water they can be more trouble than worth. Especially if water pressure is low.
Guessing you have 2- 75 gpd membranes. Most common.
City water?
Correct. Maybe I should sell it and get a new unit...
And it's Blue Springs, MO which uses 3 different sources for their water, including Independence, MO, which I know uses chloramine.
 

Saltyreef

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Okay, I confirmed that my pressure guage just doesn't work. Hooked it up directly to the faucet and it didn't move.

In 60 seconds, I made about 435 mL of RODI water and about 460 mL of waste water, so it's 0.95. I'm confused by how you phrased your note above though. Is this appropriate or no?

I hate the idea of spending even more money here, but I'll take a look at the unit you're suggesting. Can you send me a link to the specific one? Keep in mind, I have to deal with chloramines in my water. :-( Thanks,
--Kyle
So youre essentially running less than a 1 to 1 ratio that could be contributing as for a standard rodi 3x to 5x is recommended.
Heres the link to the unit i use and the recommendation for waste to product ratio.


Screenshot_20200111-152631_Adobe Acrobat.jpg
 

theMeat

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Pretty much a unit is a unit. It’s what you put in it, as far as which type and size or cartridge, membrane etc that makes it

personally would go to BRS website and order a replacement filter kit/package with all new cartridges and membrane, new properly sized flow restrictor, and auto shut of valve. Would be glad to make a list of it for you.
How many cartridges does your unit have?
 
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theMeat

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So youre essentially running less than a 1 to 1 ratio that could be contributing as for a standard rodi 3x to 5x is recommended.
Heres the link to the unit i use and the recommendation for waste to product ratio.


Screenshot_20200111-152631_Adobe Acrobat.jpg
From what I’m understand Kyle is running a dual membrane. So the waste water from first membrane goes into second, and reduces his waste ratio greatly.
 
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kyley

kyley

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So youre essentially running less than a 1 to 1 ratio that could be contributing as for a standard rodi 3x to 5x is recommended.
Okay, I guess technically I'm just over 1:1 because that sheet said to divide it the reverse of how I did. 1.07, but irrelevant. :)

Pretty much a unit is a unit. It’s what you put in it, as far as which type and size or cartridge, membrane etc that makes it
How many cartridges does your unit have?
4 (sediment, carbon block, catalytic carbon (though I've heard different things on which should be first), then the Membranes, then the DI cannister.

From what I’m understand Kyle is running a dual membrane. So the waste water from first membrane goes into second, and reduces his waste ratio greatly.
That's correct.

One more note after looking at the flow of all the tubes... What is in the picture here? After the 3 filters, the line goes into the bottom of that piece, comes out the bottom, and goes into the membrane. The two membrane output lines get combined and go into the top of that piece, come out the top of that piece and go into the DI cannister. What is the purpose of this piece? Should I remove it and have the lines go directly in?
IMG_20200111_161500.jpg

Thanks,
--Kyle
 

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