Holy Chlorine, Batman!!

[duraleigh]

Hi, Folks,

I'm not sure if there is anything to be learned from this but just had to post it. A coworker asked me to test his pool water. He had relied heavily on an inline chlorinator and pucks to keep his water clear for years. He suspected he had a problem cause his test strips gave no reading and he asked me to test a sample for him with Ben's kit. Here's what I got

FC - 44
TC - (what's the point?)
pH - 6.8 - 6.9
Alk - 80
CYA - 120 plus

I told him that if he didn't like the color and pattern of the liner not to worry 'cause it would be gone when he got home!!

Amazingly, 10 days later of adding nothing and his FC is down to 22 and his liner DID NOT fade one bit. I'm assuming the buffering of the CYA protected him....I can think of no other reason he has any color at all in his liner.

Again, I doubt this has any value to anyone, but I simply had to post that FC - 44

[vanhout]

Yikes. What was he thinking?

[mwsmith2]

Jeeez. That's pretty high. I bet he's going to need a TON of borax to get his pH up. I'm sure it's below 6.8. It's gotta be if he burned enough tabs to get to 44 ppm Cl

Michael

[duraleigh]

Michael,

I forgot to add that that his pH was 7.2 the second time I tested for him (10 days after the 44 - FC.) I have no idea how that was possible.

[MaryLee]

Wow!! At a CYA or 120+, he would need to be at 25 PPM to shock the pool....44 is crazy. What about his hair and swimsuit....did he notice anything bleaching??

[PoolDoc]

Yikes. What was he thinking?

With most test methods, there's no way to determine 44 ppm. OTO will be dark orange at that level; DPD tabs will be clear. So, he may have thought his chlorine was too LOW!

I forgot to add that that his pH was 7.2 the second time I tested for him (10 days after the 44 - FC.) I have no idea how that was possible.

The Taylor reagents are stabilized against chlorine, but not to 44 ppm. As far as I know, the only reliable method of testing pH, when the chlorine is that high, is a RECENTLY CALIBRATED pH meter.

Ben
"PoolDoc"

[waterbear]

The Taylor reagents are stabilized against chlorine, but not to 44 ppm. As far as I know, the only reliable method of testing pH, when the chlorine is that high, is a RECENTLY CALIBRATED pH meter.

Ben
"PoolDoc"

DITTO THAT, Ben! At that high a chlorine level just about all the phenol red would probably have converted to chlorphenol red which is yellow at a pH of about 5.0 and turns purple at a pH of about 6.6 with shades of orange, red and red-purple in between, similar to phenol red from ph 6.8-8.2. So, if the pH appeared to be about 6.8 (yellow orange with phenol red test block) it was probably MUCH closer to about 5.2!!!!!!!!!!!!!!!!!!!!!!!!!!!) Trichlor is VERY effective at lowering pH, as we all know too well
Once the chlorine level started to drop to 22 ppm then the sodium thiosulfate in the pH indicator might actually have had a chance to kill some of the chlorine and less of the phenol red would convert. Hence the apparent jump in pH. I would have to guess the pH was STILL probably at or below 6.0 however. The indicator color would be a mixture of both the phenol red and the chlorphenol red in some unknown proportion at this point so the pH reading is still probably bogus.

[PoolDoc]

Here's what I got

FC - 44
TC - (what's the point?)
pH - 6.8 - 6.9
Alk - 80
CYA - 120 plus
...

Amazingly, 10 days later of adding nothing and his FC is down to 22 and his liner DID NOT fade one bit. I'm assuming the buffering of the CYA protected him....I can think of no other reason he has any color at all in his liner.

Actually, such posts have quite a bit of value, at least to me. They provide me with external confirmation of some of the points I've made here. For example, I assume he'd been swimming in the pool with no observed ill effects? That's what I'd expect, but it's totally contrary to what's found in all the literature.

Ben
"PoolDoc"

[duraleigh]

Hi, Ben,

No swimming yet. We're in Raleigh, NC, and while my pool is temporarily drained, I suspect most pool temps to be in the 60's.

He's a mercenary sort of guy......maybe we could all chip in and get him to take a dip.....see if he turns into an albino!! KIDDING! KIDDING! KIDDING!

Yesterday (10 days after the 44 FC) was when I got the 7.2 pH and 22ppm Cl.

Actually, one good result. After seeing Ben's kit, I'm pretty sure he is a convert and will be ordering the PS234 in the very near future

[CarlD]

How could his pH go up? Is his pool open? Is the filter running? Then let's not forget our T/A lowering procedure....

"...then when the pH is below 7.2, aerate your water to raise pH..."

So his water is aerating and raising the pH.

Of course, this assumes that the 7.2 is vaguely accurate given Ben's caveats.