RO/DI System; DI Canister

[jeffbhester]

Hello Everyone!

New to reefing and am just about to start cycling my live rock in a Brute 32 gallon trash can. I ordered an RO/DI system (this one here... https://www.marinedepot.com/marine-depot-kleanwater-4-stage-advanced-ro-di-system-100-gpd) and have made about 50 gallons of product water so far (I ran the system for quite awhile at the beginning to flush everything and now have about 25 gallons of mixed saltwater in my Brute bucket). My input water from the tap measures around 375 TDS, after running through the RO membrane it's about 110 TDS, and it was reading 0 TDS after the DI filter. The indicating resin on the DI filter is about 3/5 gold now and it just started reading 2 TDS after the DI filter, it's still reading 110 after the RO membrane.

Few questions... does this seem like the DI resin was a bit short lived, only 50 gallons of product water? Or is that normal with the higher TDS levels from my tap? Would it be a good idea to add more stages to my setup? And lastly, I went on marinedepot to order a replacement DI filter and the picture of what I have in my DI canister matched the picture of the Chloramine-X GAC Carbon Filter, is there a possibility there was a mix-up?

Thanks for any help and let me know if there's any more info I can provide!

Jeff

 

[Shirak]

Something not right with the RO stage. If it's a typical 98% rejection membrane you should be reading around 8 tds after RO going into the DI. Sounds like some waste water getting into the RO water. Maybe something isn't quite right with the line hookup?
The center tube coming out of the end opposite from the pressure gage should be going to the DI.

 

[homer1475]

All the external canisters are the same. Doubtful there was mix up.

The internal canister is slightly different then what you would find in a media reactor.

 

[jeffbhester]

Something not right with the RO stage. If it's a typical 98% rejection membrane you should be reading around 8 tds after RO going into the DI. Sounds like some waste water getting into the RO water. Maybe something isn't quite right with the line hookup?
The center tube coming out of the end opposite from the pressure gage should be going to the DI.

Ah interesting, I'll redo the lines and see what values I get, thanks for the response!

 

[homer1475]

Might also want to check to see if the RO membrane is sitting in the canister properly. If it's not seated properly, water can make it's way past the membrane resulting in high TDS out like your seeing.

 

[Shirak]

Well I watched the videos and looked at the pdfs They were not a lot of help although there were a couple points in the first video that showed the tubing hookups and which line was which. It's possible the RO membrane is not fully inserted into the housing but usually you can't close the other screw cap end piece if this is the case.

 

[homer1475]

Care to send some pics? We could help diagnose the issue if we could see how it's hooked up.

 

[K7BMG]

Your system have a flush valve?
If so is it in the correct position for use.
What is your operating pressure?

One key thing about the TDS probes.
Make sure they are in the right position.
With the T disconnected look through the end and make sure the pins are on the left and right sides. Turn them if they are not. The water should go through the pins not around them.

Yes your DI stage will get used up quickly with it only having one canister.

 

[K7BMG]

If your going to add canisters I would break up your DI into three sections.
1st canister should be Cation, 2nd canister should be Anion, 3rd mixed bed.
You will go through a lot of Anion typically.
I will go through three to four canisters of Anion to one of Cation.

 

[jeffbhester]

Care to send some pics? We could help diagnose the issue if we could see how it's hooked up.

For sure, will send some shortly

 

[jeffbhester]

Your system have a flush valve?
If so is it in the correct position for use.
What is your operating pressure?

One key thing about the TDS probes.
Make sure they are in the right position.
With the T disconnected look through the end and make sure the pins are on the left and right sides. Turn them if they are not. The water should go through the pins not around them.

Yes your DI stage will get used up quickly with it only having one canister.

It does have a flush valve, I've been using it at beginning and end of making water, turning it parallel to water line to flush and then perpendicular to make water. Operating pressure is at 63. Good to know about the probes, will check those out as well, and thanks for the info on the extra stages!

 

[K7BMG]

Forgot to ask, your TDS meter has three probes?
And they are
1 source
2 after RO
3 output / product

 

[jeffbhester]

Forgot to ask, your TDS meter has three probes?
And they are
1 source
2 after RO
3 output / product

Ah sorry, no, just 2 probes, 1 is after RO and the other is on output. Before I setup the system I used one of the probes to measure my source water which is where I got the 375 reading from.

 

[K7BMG]

Gotcha.
Yes I have to agree that the RO should be pulling more out.
Your ratio is off from 375 to 110.

Now my ratio is 185 to 4, but I also have two membranes.
Cant compair as my worl to yours is like Earth and Pluto.
But it should be better than that IMO.

 

[K7BMG]

I would also call Marind Depot and get their thoughts.
They should have better information as its their product.
I dont know if the do the assembling and all but they did the research and chose the internals.
So IMO they should have the best answers.

 

[jeffbhester]

Went out and pulled the RO membrane out and reseated it, I'm now reading in the high 20's ppm after the membrane instead of 110! And it's steadily dropping as well. Not really sure what I did different, maybe just not seated properly when I first installed or got bumped while I was setting it up on my wall. I think my DI filter might be about shot now though so time for replacement. Thanks again everyone for all of your comments, I'll get the new resin and see how long it'll last me now that the RO membrane is functioning better!

 

[K7BMG]

Good news. Yup sounds like things were not seated just right.
Did you check the TDS meter probes, and were they properly installed?

 

[Shirak]

The RO water will be high initially and then drop down to it's final level after 10 minutes or so. To help preserve the life of your DI resin it's a good idea to have a bypass between the RO and the DI so you can run it for a few minutes if it's been sitting for more than a day, before collecting rodi water. I use the RO water for my espresso machine and watering the houseplants!

If your initial tap water measurement is correct I estimate around 8 TDS after RO with a 98% rejection membrane.