How long to reduce TC by 1 ppm

Jun 10, 2009
2
I found your web page and decided to convert my pool from Baqucil to Chlorine after 12 years of headaches with Baquicil. The local pool store made a killing on me with all their snake oil.
I started the conversion on June 8 after reading and studying your webpage and all the forums pertinent to the conversion. Things have gone according to plan and the pool went through all the color phases and it is now crystal clear. My TC has dropped 4ppm during the night on June 10 amd it dropped 3ppm last night. I've used up most of my R-870 and R-871 and have reordered more. I'm only adding chlorine to elevate it up to about 15ppm after sunset. How many nights does it take for the TC to drop only 1 ppm? I've vacuumed and brushed each day and all the visable gook is gone. Pool looks beautiful and I'm looking forward to the completion of the conversion. Sam's Club has cartons of Clorox bleach, 182 ozs. three bottles per case for $8+change. Charlie Lesser
 
Hi Charles!

Glad to hear things are going well. I don't think anyone can give you definite answer on when your conversion will be done, but I'm guessing you're getting close.

You mentioned that you are only getting your FC up to 15ppm after sunset. What is the FC during the day? I'm guessing your CYA is zero, so the FC will be cooking off fairly quick in the sun. If your FC is getting too low during the day, you might be fighting the beginnings of an algae bloom each night.

Also, just to be clear, it is your free chlorine (FC) you want to drop by no more than 1ppm overnight, not your total chlorine (TC). TC is FC + CC. You want your CC to be no greater than 0.5 ppm. You may already be clear on this, but you mentioned TC instead of FC.
 
The total amount of time it takes to finish the conversion varies pretty widely from pool to pool. By measuring the FC loss overnight for several nights in a row, you can get a sense of how quickly you are getting there in your particular pool. From the very limited information you gave, I would guess that you have about three nights left, but that is only a rough guess because of the limited information, it could be longer or shorter.
 
My typo , I meant FC instead of TC. I measured the FC at 7:30PM today and you are correct, the FC was 0. And yes, there is no amount of CYA in the pool to stabilize any of the Chlorine. So I added 375 oz. of Clorox at 8:45PM with the circulator going to get the FC up to 15ppm. I'll measure FC at 10:00PM and again at predawn. It never occured to me that any algae would get started with all the Chlorine I've added during this past week. Tomorrow I'll add more Chlorox at noon to 15ppm and again at dark to 15ppm. I guess I've been trying too hard to conserve my R-870 and R-871. I ordered more today so on with the show.
 
No not really. The water isn't safe for swimming, but algae won't be an issue. It takes algae about two days to really get going if you start without any algae at all. He will be shocking each evening less than 12 hours after the FC level gets too low.
 
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