Chloramines in City of Austin Water

[Sherita]

Yes, I'm just curious, that's all. I've been told that running chloramines through the ro membrane can damage it. I'm just wondering if any chloramines are mmaking it through your carbon.

[victoly]

Seems like a good thing to know, I'll get on it this weekend.

[Buckeye Field Supply]

...any amount of chloramine that makes it through the carbon to the membrane can cause damage to the membrane over time and dramatically shorten the life span of the membrane.

That is true for chlorine, but not necessarily true for chloramine.

You can expect damage in as little as a 1,000 ppm hours from chlorine, but they tested Filmtec membranes up to 300,000 ppm hrs and didn't see damage from chloramine.

The problem is that if you have chloramines, you likely also have some free chlorine.

If you have chloramines, and if you have adequate carbon contact time, and if your pH is over 7.2, you may also see membrane damage and reduced DI life from ammonia. Below 7.2 the ammonia will be present as ammonium and should be largely rejected by the membrane.

Russ

[victoly]

Our pH is generally well above 7.2 out of the tap.

[victoly]

For sherita, I tested chloramine out of the 2nd CGAC (mechanical->CGAC->pentex->sample) and got 0.00. My CGAC/pentek are now one month old. I'll test out of that port every month to see if I start to get some chloramine creep.

[victoly]

About 5 months out and still no measurable total chlorine.

[victoly]

So i finally got my Hanna 761 in today. It reads total chlorine in the ppb range (+/- 5 ppb)! My RODI with CGAG reads 12 ppb or 0.012 mg/l. My CGAG and pentek are roughly 6 months old, and I'm guestimating that they have produced ~500 gallons of total water. I'll take readings of the whole system tomorrow and see what I come up with.

[victoly]

Total chlorine out of the CGAC (pre-pentek) is 0.05 mg/l. I'll test out of the pentek (into the RO membrane) when I get an opportunity.