Bleach's affect on Alk?

It was my understanding that bleach use would eventually cause PH to rise, but will it also increase Alk?

A few weeks ago I had my Alk down to 150. Tested my fill water, and it's 320. I had to add a few inches of water, alk went to 180. Just tested again today, PH is 8.2 and Alk is 250.

I've only added bleach to my pool, at the rate of .75 gal of 6% per night in my 21,200 IG pool.

Do you think the bleach is what's causing my alk to rise so fast? I've added muratic acid this afternoon, hope to again drop the alk and aerate as needed. Since high alk seems to be a continuing "problem" (is it really in a vinyl lined pool without SWG and/or heater?), I plan to try to get my alk down to 100.

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Originally Posted by Rangeball

It was my understanding that bleach use would eventually cause PH to rise, but will it also increase Alk?

A few weeks ago I had my Alk down to 150. Tested my fill water, and it's 320. I had to add a few inches of water, alk went to 180. Just tested again today, PH is 8.2 and Alk is 250.

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No it doesn't. However, alkalinity will rise and fall with pH, so your reading at pH 8.2 will be higher than at 7.5. I'd say alkalinity readings at "out of range" pH are not something to worry about. Get the pH down, then retest your TA.

Thanks :)

That's the plan.

I'll test PH and Alk again tomorrow morning. That should give the acid a good 17-18 hours to circulate (I run my pump/filter 24/7).

Tested the pool this morning. PH down to 7.8, Alk down to 190. I'm gonna hit it with more acid this evening, try to get the PH down to 7.2 then aerate.

One thing I've noticed, getting the PH/Alk down made a big improvement in water clarity. Our water had been getting a bit "less clear", not cloudy at all but just not "crystal" clear. Dropping the PH made a noticeable improvement. Looks like a bowl full of fresh cleaned liquid glass again :)

After adding more acid, PH dropped to 7.2. Alk didn't budge though :(

Oh well, I have a vinyl liner, so not going to worry about it unless it causes a problem down the line. Water looks and feels fantastic.

Another thing I noticed, when the PH was high, the liner had a somewhat slick feel to it. Not like a biomass film, just a bit slippery.

Now that the PH is down, liner feels squeaky clean :) Whether that's a function of PH or bleach being more effective at lower PH, I like it :)