Shocking

[jrv331]

Say I want to shock my pool to 15ppm and my FC tests at 5ppm. Would I add 10ppm of chlorine or do you shock with the amount you need and forget about your FC level? Dont want to damage my vinyl liner - its already fading.
John

[DavidD]

Say I want to shock my pool to 15ppm and my FC tests at 5ppm. Would I add 10ppm of chlorine or do you shock with the amount you need and forget about your FC level? Dont want to damage my vinyl liner - its already fading.
John

Yes, add the amount of shock (= to 10ppm) you need. This will bring your FC to 15 or "shocK" level. Shock levels depnd upon your CYA level so check out Ben's Best Guess chart http://www.poolforum.com/pf2/showthread.php?t=365. It is what we use as a guide.

Dave

[Amir]

Shock is the level of chlorine in the pool. You just need to add enough chlorine (shock) to raise the FC to the level you want (in your case 15 ppm) so just add enough to raise it 10 MORE ppm.
Amir