what does an exhausted DI cartridge look like?

[guyduquette]

I have a color changing DI cartridge on my Maxxima RO/DI system, but I've never seen it happen.

What changes color. The line about half way through will rise or something?

 

[biggyclops]

what is your TDS? reason is that it isn't a good idea to just use the color change as an indication of spent DI... IMHO...

 

[RayD]

You'll see it turning brown from the bottom up. When it's all brown it's toast.

 

[this is me]

Good question. I was wondering this myself. It says color changing DI, but it doesn't what color it will change to.
I usually just go with the TDS reading out of the DI. If it's more than 5, I change to a new cartridge.

 

[stevenp]

IME the color change is VERY noticeable. It changes from bottom up, black to brown.

 

[bill120mph]

it turns a sandy brown, but I would definitely get a meter

 

[guyduquette]

Well mine looks brown. I bought it used a year ago. It's now getting white from the top down (about 1 1/2" or so)

My TDS reading still says zero though. So, should I wait until TDS goes up before I change it.

 

[guyduquette]

could be the plastic that is brown though?

 

[biggyclops]

i would wait... no sense in wasting money if there is nothing wrong

 

[delta]

You should test the TDS, the color change is only an indicator as soon as you get a reading of anything more than 0 you should change it out.

 

[guyduquette]

So, TDS is the most important reading of the health of my entire RO unit, or just the DI?

 

[this is me]

It's the entire unit.
Get two of these dual inline tds meter and stick it in your unit
http://www.marinedepot.com/ps_viewi...lTDSMeter&utm_campaign=mdcse&site=google_base

With a total of 4 probes, measure
1-The input of the first cartridge. This will tell you the tds of your source water
2-The output of your last cartridge(most likely the DI). This will tell you your RODI tds. Should be 0.
3-The input of the RO cartridge. This will tell you the tds before the RO.
4-The output of the RO cartridge. The RO cartridge should be removing 95-99% of the tds of reading 3. This reading will also tell you when to change the RO cartridge.

Pretty much bulletproof...I think.

 

[guyduquette]

Wow. great idea. That will narrow down the problem!