I need help, never seen this before

[Reddogdan]

I was trying to show my brother why he can't keep chlorine in his pool and hit a brickwall. He has been using shock and tabs for two years. I expected his cya to be off the charts. I ran CYA and it shows 0. This pool is 8400 gallon vinyl, above ground pool. I can understand now why he has no chlorine. But why does he have no CYA? He said he threw 3 bags of shock in last week and still no CYA.

 

[duraleigh]

Perhaps the "shock" was cal hypo.....there is no CYA in it.

What did he do with his pool over the winter? Did he put a cover on it, partial drain?

 

[Reddogdan]

Good job, it is cal hypo and the pool was covered all winter.