Polyquat algaecides: Mode of Action


Well-known member
Nov 19, 2011
Well I did test CC the morning after the first overnight shock and it was still 0, but I guess any formed chloramines would have been burned off in the process.


Jul 17, 2012
Re: Polyquat algaecides

I just realized that one of the recommendations for weekly maintenance of a seasonal pool is to add polyguat once a week. I bought hth super algae guard but I am thinking it might not be the right one. It's dim ethyl benzl ammonium chloride 30% and dim ethyl ethylbenzyl ammonium chlorides 30%. Thank you

chem geek

TFP Expert
LifeTime Supporter
Mar 28, 2007
San Rafael, CA USA
That recommendation is because for a seasonal pool stabilized chlorine is used so the CYA level builds up and you need an algaecide to prevent algae. If you instead use chlorinating liquid or bleach at a fixed CYA level, then you won't need any algaecide, but you need to be diligent about maintaining the FC level for your CYA level.

As for the algaecide, you've got the wrong stuff. It's a common linear quat so will tend to foam and it will break down faster from chlorine. It's less expensive, but you get what you pay for.
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