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View Full Version : Added bleach to shock pool, now ph is too high



ginar
04-14-2011, 01:58 AM
We recently purchased a home with a pool that was full of green muck. I have no pool experience, but after reading lots of the threads on this site relating to algae, I decided on a course of action... shock the pool hard and keep shocking and brushing and vacuuming until everything is gone.
My readings at the outset were
30,000 gal. pool
FC - 0
TC - 0
ph - 7.4
TA - 90
CYA - 45

I added 12 gallons of bleach after sunset this evening. A few hours later my ph was between 7.8 and 8.
Is it normal for the ph to rise significantly after adding bleach to shock the pool?
I added the prescribed amount of muriatic acid to combat the rise. Will the period of high ph make the chlorine less effective?

It is hard for me to tell what the FC/TC is right now because I only have a small oto test kit while I wait on the full kit to arrive by mail.

Thanks for any help you might be able to give!

PoolDoc
04-14-2011, 08:38 AM
Not only normal, but typical. And, not necessarily a problem (see http://poolsolutions.com/gd/hiphpool.html)

Actually when you're cleaning gook, it's often better to be at a high pH, since the intermediate products that form at a higher pH, as the chlorine 'burns up' the gook tend to be less noxious than the ones that form a lower pH levels.

Anyhow, 10 gallons of 6% bleach on a 30K pool is about 20 ppm of chlorine. At levels above 5 ppm chlorine, most pH tests are invalid. (Taylor's are probably OK to 15 ppm). So your pH isn't necessarily what you think.

Repost with post chlorine test results.

Also, don't panic if you keep having to add chlorine: it's not unusual for cleanup to consume 100+ ppm of chlorine! If at all possible, filter and vacuum, too. If you REALLY have a lot of gook, it's very hard to clean that up chemically.

PoolDoc.