How high chlorine level in vinyl pool?

[hokulii]

I have been reading up on the no CYA, plenty of ammonia issue, me too Same as last year, this is a cycle I'd like to break.

I understand what needs to be done, but have (at least) one question. Is there a maximum level of chlorine that should go into a vinyl lined pool without damaging it?

Thanks, D

 

[Casey]

Please refer to this chart in Pool School on Chlorine/CYA ratios.
pool-school/chlorine_cya_chart_shock

 

[JasonLion]

In a vinyl pool, you don't ever want the FC level going more than about 50% above shock level at any time. You can find shock level in the table Casey just gave a link to.

The best thing to do is to add enough chlorine to get to shock level. You can the wait 30 minutes with the pump running, test the FC level, and do it again.

 

[hokulii]

The minimum CYA on the table is 20, for a shock level of 10. I have 0 CYA and a bunch of ammonia. I shocked to 50 last night and saw a difference in water this morning. What will high chlorine bursts do to the vinyl?

Thanks

 

[JasonLion]

It has a lot to do with how high the FC level actually got and for how long. The initial reaction between chlorine and ammonia is very fast, faster than you should be pouring bleach into the pool. You would never have reached anything near 50 ppm, or even 10 ppm, in the pool as long as there was ammonia around to react with.

An FC of 50 with really and truly zero CYA can corrode metal noticeably in days and can shorten the lifetime of the liner in days. Hopefully you didn't ever get nearly that high.

 

[hokulii]

Thanks Mr. Lion. I'm not sure I fully understand one thing you wrote "faster than you should be pouring bleach into the pool"?

I put 14 jugs of 6% bleach in my 12,500 +- gallons of water. I read something on a post that lead me to calculate each jug at about 3.75 ppm, thus 14x3.75= 52.5. I did an ammonia test (aquarium test strip) that indicated about 3 ppm.

I've added 3.75 lbs of CYA over the last several days and am still seeing the black dot when all the water is out of the squirt bottle and in the cya test vial. With the ammonia I wonder if the CYA is being consumed before it can accumulate/take hold in the water???

I have seen some clearing of the water, I put a black stone on the lowest step in the pool, couldn't see it yesterday but could this morning.

On another issue my pool light just burned out (the day after the power switch for the pump broke ). The directions for changing the bulb don't say to drain the water below the light to replace it, but it does say to fill the water back up when done??? I haven't had to do anything with the light before, kind of makes sense to have to drain below the light so the fixture isn't full of water... do I need to drain it down?

Thx, D