RODI filter exhausted....already?

[reef tank 2.0]

Back in March of this year, I replaced the RODI cartridges, except for the membrane on my 75 gallon RODI system.
I run the system about twice a month, just enough to fill up the mixing barrel (55 gallons) after a water change. Then occasionally a good 10-20 gallons to fill up the fresh water barrel.

Last night, when I was topping off the fresh water bin, I checked my TDS sensors. TDS sensor #2 was reading 5, and the #3 sensor was reading 2.
Normally, when I see these levels above 1, I start getting concerned and all filters will be replaced soon after.

With my filters only being 5 months old, and running twice a month, I am left wondering how this could be possible. Maybe it's because I did not replace the membrane back in March, maybe that's causing my numbers to increase. If I replace the membrane, is it ideal to replace all other media as well? Anyone else experience this?

 

[first29gallon]

Do you flush the system each time you use?
Also, are those readings right after you turn it on or after a while they were still above .00?


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[reef tank 2.0]

I flush the system for about a minute before starting to fill the barrels. I usually check the reading after its been running for a good 5-10 minutes.

 

[mcgyvr]

TDS right? Not TDI?
.05?
Which sensor system do you have? Thats quite accurate if thats true..
Typically they just go by whole numbers..
Where is each probe located? You have all of them after the DI stage?
Typically one would be post RO then post DI,etc...
A RO is only 96-99% effective and will NEVER have a TDS of zero at its output..

Are you on a well?
What is your incoming TDS?

Typically people replace RO membranes every 3-5 years..

The whole small decimal numbers is confusing here..

 

[mcgyvr]

Also.. prefilters (carbon block/sediment,etc...) do not reduce TDS.. You typically replace them every 9-12 months or monitor the pressure loss if you want to get fancier to see when they are getting clogged thus causing RO membrane pressure to be lower thus lowering its efficiency..

 

[reef tank 2.0]

Sorry, yes. TDS...not TDI
I guess there is no decimal point. Full numbers rather. (I am updating the OP)
Here is the inline TDS meter I have. http://www.buckeyehydro.com/trm1-tri-inline-tds-meter/

Going off memory, the incoming TDS is high 100's, maybe 190's. I look at it from time to time, but not often. My focus is always on the 2nd and 3rd reading. The 2nd, and 3rd reading is always at 0, until I checked it last night.

It could be something as easy as allowing the system to flush longer, before running to the water containers.

 

[nereefpat]

You're right..that isn't much lifespan.

A couple things that can help:

Flushing; this was mentioned, but it needs explained. You want to run water through the RO, but NOT through the DI for a while. The first wave of RO will have high TDS that can chew up your DI resin.

Vertical mounting of the DI; Vertical mounting allows you to get all the resin used up instead of the water channeling through it.

CO2; supposedly in some parts of the country there is high co2 in well water, which can cause you to go through resin quickly. You can degas the water before sending it through the filtration system.

 

[reef tank 2.0]

I will allow the water to flush tonight for a lot longer. Then I'll see what my numbers are.
Never had this problem before, so this is a new issue to me.

 

[mcgyvr]

Sorry, yes. TDS...not TDI
I guess there is no decimal point. Full numbers rather. (I am updating the OP)
Here is the inline TDS meter I have. http://www.buckeyehydro.com/trm1-tri-inline-tds-meter/

Going off memory, the incoming TDS is high 100's, maybe 190's. I look at it from time to time, but not often. My focus is always on the 2nd and 3rd reading. The 2nd, and 3rd reading is always at 0, until I checked it last night.

It could be something as easy as allowing the system to flush longer, before running to the water containers.

Much better..
However I'm assuming that your 2nd is after the RO and based on the rejection rate of your membrane (96-98%) with an incoming TDS of 190 or so then 5 seems totally fine (97%)..
To have zero would indicate something out of the norm to me actually or just show the meter isn't that accurate as no RO is 100%

Now a positive number post DI stage is indicative of end of life for the DI.. However it could be channeling/high co2,etc..
You didn't answer if you have a well or where the probes were located in the system..

 

[reef tank 2.0]

sorry....No, I do not have a well. I have city water
As for the locations of my probes, I'll have to double check tonight when I get home. Haven't touched it in a few years, other than the meter display.

 

[outssider]

a positive number post DI stage is indicative of end of life for the DI.. However it could be channeling/high co2,etc..
You didn't answer if you have a well or where the probes were located in the system..

+1

This is your problem. If the Di is horizontal, It's most likely channeling. If it's vertical it's most likely shot......Most resin is color changing so you should be able to see the change in color when you look through the clear container

 

[reef tank 2.0]

Alright, here are my findings

incoming water is measuring: 186
#2 TDS:17
#3 TDS: 3

#2/#3 are always at 0-1.

the red meter which is measuring the incoming water, is placed in between the incoming water source and the sediment cartridge.

the green meter which is measuring the water that is going to the water bins, is placed in between the resin cartridge, and the barrels.

the blue meter is placed in between the membrane, and the resin cartridge

Here is a picture of the set up. Again, it's been running this way for years. Hopefully it was/is correct, but I haven't had any issues till now with water quality.

(and before you ask, the wood shims behind the booster pump are to quiet the pump vibration noise. It was a quick fix, and I just never revisited to make it prettier)

 

[tdlawdo]

Have you checked with your city to see if they use chlorine or chloramine to treat the water.? You may need a different type of carbon block. Also check out TDS creep. Looks like your resin needs changed. May need to step up your canisters to two carbons and two resins. Check out the BRS YOUTube vids on RODI.


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[reef tank 2.0]

I'm going to contact the water company today after last nights head scratcher.
Last night I received a fresh batch of media for my RODI unit. I had a new membrane on hand. So I replaced all. Once doing so, I let the water run to waste for a good while (or so I thought). Once I turned it off, I continued to fill the water bins and check the TDS meters. The middle meter read 6, and the outgoing meter read 3. So now, with new media, why on earth would my readings not be ZERO?

As I mentioned I will call the water company today. Last time I changed media, my readings were at 0. Obviously for a short time, but still.

 

[outssider]

If you're getting 6 before the resin and 3 after the resin, then somehow the water is not going through the resin properly. There may be some channeling going on in the resin chamber.....calling the water company isn't going to do any good....

 

[reef tank 2.0]

So what do I do at this point?

 

[hkgar]

So what do I do at this point?

I would double check that all the connections are correct and that water is going in the in port and out the out port of the canisters.

 

[reef tank 2.0]

I will be going down there in about an hour, I will check where everything is going to. I'll report back with a diagram showing all

 

[reef tank 2.0]

OK, here's what I have.

 

[Reefer40b]

I would double check that all the connections are correct and that water is going in the in port and out the out port of the canisters.

I would also check this but seeing how you had no issues in the past I assume you never disconnected the RO tubing, but just in case the IN should run down the outside of the DI cartridge and then be forced UPward thru the DI risen.