I want to shock to reduce chloramines but....

Hi All,
I want to use a chlorine based powder shock to reduce combined chlorine but have a few questions. I used to always use the non chlorine based shocks until I read they are garbage on poolsolutions.

I always heard stories that excessive chlorine concentrations (ie shocking) will bleach vinyl liners. I know that has to be an urban myth but wanted to ask. Second, my CYA levels are >150ppm. I have since stopped using pucks and gone to bleach but am wondering with all that CYA will my pool be stuck at 25ppm chlorine for 2 weeks or does it not apply? Using the "best guess" chart I need to bring it up to 25ppm to shock?

Thanks for the help!
J.

Hi,
Proper "shock" levels will not bleach your liner, but you have to be careful not to get it too high...hence the "Best Guess" table. With your CYA as high as it is, though, you're likely to have trouble getting your Cl high enough to do any good. I strongly suggest that you do partial drain/refills to lower it, if that's feasible for you.

If you have combined chlorine in your pool, then when you shock, they will lower the Cl level fairly quickly. Even if not, I don't think you're stuck with 25 ppm Cl for 2 weeks, probably more like 3-4 days....

Janet

Hmmm, I knew the CYA was going to cause me some grief......

Are the non chlorine based shocks really that bad? I hate to drain the pool but if it's my only option then I have no choice.

Is it safe to drain a vinyl liner pool halfway then refill without causing damage to the liner?

You can safely do a partial drain in a vinyl pool. You're probably going to need to do several partial drains to get your cya reading to a more manageable level.

I partially drained and refilled and now have a cya of 70ppm. I'm happy with that. Thanks for the tip.
J.

Quote:

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Originally Posted by cruzmisl

I partially drained and refilled and now have a cya of 70ppm. I'm happy with that. Thanks for the tip.
J.

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congrats!

dan