TDS going UP after second DI stage

[trmiv]

Hoping someone can help me with this. I recently changed all my filters in my RODI unit and at that time I added a second DI stage to my unit. Both my DI stages are filled with the BRS mixed bed color changing DI resin. When I packed these I tapped, packed, tapped some more and packed some more to make sure there was no channeling.

The first stage of the DI is getting 3 TDS water from the RO stage and putting out 0 TDS water. The second stage of the DI is then raising the TDS to 6! This is confirmed both with my inline dual meter and a HM handheld unit.

When I first installed this second stage last month it was producing 0 TDS. No idea when it started with this. I’ve made a decent amount of water but not more than around 200 gallons.

Here’s a pic of the second stage. Notice how spotty it looks? The first stage has barely any color change near the bottom.

How on earth is it possible for the first stage to pass 0 TDS water and the second stage to then raise the TDS?

 

[Big G]

Give BRS a call. They have been very helpful in the past.

 

[thegreyanenome]

sounds like we need the #reefsquad

 

[Crabs McJones]

Weird, that doesnt make sense. How long after replacing the din resin did you let it run? I know with mine I'll register tds for a little bit as its flushed and filtered out of the system.

 

[JoshH]

Very common for single type resins to "Raise" the TDS after. This happens when anion or cation resins interact with some of the dissolved solids and change there ionic charge which shows up as TDS. Your second stage will remove these altered molecules. This is actually discussed briefly in one of BRS' videos I'll have to dig it up.

I have 0 going into my Anion stage and 7 leaving it, cation gets rid of this and then it goes through a final mixed polish.

Are they both mixed bed color changing?

 

[trmiv]

They are both BRS mixed bed color changing DI

I ran about 3-4 gallons through it after I changed it.

One thing I noticed is even right after this was added, the TDS after this last DI stage would always be like 10-12 right after I turned the unit on, and then would go down to 0. This was while it was receiving 0 TDS water from the first stage.

It obviously appears it was channeling some, but it makes no sense that it got 0 TDS water from the first stage which is barely exhausted, and then exhausted this quickly, basically in a little over a month.

 

[JoshH]

They are both BRS mixed bed color changing DI

I ran about 3-4 gallons through it after I changed it.

One thing I noticed is even right after this was added, the TDS after this last DI stage would always be like 10-12 right after I turned the unit on, and then would go down to 0. This was while it was receiving 0 TDS water from the first stage.

It obviously appears it was channeling some, but it makes no sense that it got 0 TDS water from the first stage which is barely exhausted, and then exhausted this quickly, basically in a little over a month.

You're right that is unusual, were the bags sealed when you got them from BRS?

 

[trmiv]

Yea both were completely sealed that I could tell.

 

[JoshH]

I can't think of anything that would cause that I'll have to second @Big G and suggest contacting BRS or maybe Russ at @Buckeye Hydro

 

[trmiv]

Called BRS, and unfortunately they didn't have any ideas. The guy on the phone said it's happened to him as well, and recommended switching the second DI stage to the first stage and first to the second and running it like that until it's exhausted. That really doesn't make much sense to me since I'd probably then kill this good stage in a month. What I don't get is that the first stage is barely exhausted at all and is feeding 0 TDS water to the second, how does the second stage then get exhausted in a little over a month? Shouldn't the first stage be the first to get exhausted since it's getting the 3-4 TDS water from the RO stage?

I'm just going to remove the second stage entirely and go back to one DI stage for now.

 

[KrisReef]

The second stage hasn’t properly flushed out the chemicals that were used to charge the ion exchange resins.

When I’m filling my canisters i pour di water into the end to cause those slippery beads to settle in place and then add more beads, wash again until the canister is full. Then I run them a bit and recheck to see that they are not channeling. If the resin isn’t packed tight it will continue to read TDS>1 until the recharging chems are flushed out.

 

[trmiv]

This isn't a brand new fill, I filled it last month. It was giving 0 TDS water after it was filled, but as you can see in the pic above it's almost totally exhausted now in less than a month even though it's getting 0 TDS water from the first stage. Both were packed in the same way, and the first seems to be working OK.