Do chlorine tablets ever lose potency?

ramirez41

Well-known member
Sep 20, 2023
57
Michigan
Pool Size
14000
Surface
Vinyl
I am using liquid chlorine, but occasionally use Non-Sabilized tablets when we go on vacation. (Liner pool and my calcium hardness is only at 70 so not concerned about calcium from occasional use) I also have stabilized tablets that are over a year old already. (Bio guard so they have other things in them too) I have no plan to use these any time soon as my cya is still at 80 after multiple partial drains and rain water refilling my pool from evaporation, but when my cya eventually gets low enough I may consider using them when we go on vacation which maybe a couple years yet since I have a lot of the non stabilized tablets and the cya is proving to be extremely slow to lower the rest of the way with regular water loss. Or I am reading the cya test wrong and it was actually higher than I am measuring. I expected it would have come down to at least 70 after 2 months of no stabilizer going in and enough rain that we have not had to use our hose to refill in those 2 months and I had remove water from it overflowing some.
 
overflowing some.
That's where the loss comes from. When the rain more or less matches the evaporation, it breaks even in the end. You have to overflow to reduce the CYA, and even then, for an even reduction it needs to be well mixed first.

Partial drains lower the CYA proportionately, but subsequent drains remove new water with the old so it loses efficiency with each round.

Also, it's only semantics but all chlorine is stabilized becuae it's a gas. For pools they use water (bleach), calcium (NST / cal-hypo) or cyanuric acid (Trichlor/Dichlor). They call calhypo unstabilized because it isn't stabilized with what they call stabilizer.

So they fool everyone to jacking their CYA with pucks/shock and when that becomes a problem then they tout cal-hypo in a way that doesn't make it clear they are jacking the Calcium instead. Marketing gonna market. :roll: (but you knew that part, so yay!!)
 
Thank you. I am so glad I found trouble free pool and everyone has been so helpful as I learn. I have spent many hours reading articles and forums to understand the chemistry better. So far I have no signs of the pink slim I was getting every year by the end of July.

The pool store told me I am over thinking it when I asked questions and when I went there to buy some muriatic acid they tried to talk me out of it and tried arguing that I would drop my ph too much, there is no need to lower my TA from 170, and aerating wouldn't raise my ph to get it back up. They even told me the rain would lower my ph 😂 I finally just asked if they were refusing to sell me muriatic acid. I should have taken a picture of the ph levels before and after the rain to send them. It went from 7.6 to 8 just like I thought it would.

I would skip the pool store all together, but I am still waiting on the replacement winter cover from the one I bought last year that didn't hold up and they sent a sample to the manufacturer for a warranty replacement.
 
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