Opening Pool and avoiding High Chlorine


Active member
Jul 9, 2010
minneapolis, mn
Ok i am pretty sure I asked this last year...but I can"t find it. The pool is full now and I am going to the store tomorrow.

In the past I have allways opened with ZipChlor to shock and add CYA at the same time per the information I have found on this site. I have the pool with the inflatable round ring so the water calculations are approximate as it really depend on your fill level and level of the pool. But it seems that despite my efforts using zipchlor put my chlorine up in the 30's for weeks or even a month + as the spot we have for our pool is moderate sun so it does not deterierate fast.

Last year we had to wait so long for the chlorine to drop to normal and safe levels after the zip chlor that I ended up going the peroxide route to bring it down and added chorline to bring it to a manageable level

So what is my best option for oping should I skip the zipchlor and just do Bleach for my opening shock and then add the CYA seperatly? Or should I stick with zip chlor and add it in over the process of weeks instead days or lessen the amount of zip clor I am using? i am currently using 3oz per day for the first 5 days I belive?

I want to open it up right with the least amount of lag between opening a swimming. but the month or more for it to come back down is a long time IMO


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TFP Expert
May 7, 2007
Silver Spring, MD
Your problems sound like there were because your CYA level is too high. ZipChlor contains dichlor, which adds chlorine, CYA, and lowers PH. Bleach only contains chlorine. It is important that CYA be neither too high or too low. We recommend CYA be between 30 and 50. If you use only bleach you will have to add some CYA another way. Or you could use zipchlor to start with and then switch to bleach before your CYA level gets too high.