How much liquid chlorine to shock pool

[ghostcat]

Hi. I have an 18 x 38 vinyl liner pool. About 31000 gallons. Hayward sand filter and heat pump. Opened the pool yesterday. Cloudy but blue. Using the Taylor k-2006 test kit I am getting the following results:
FC .6
CC .1
Ph 7
All 120
Cya 120
Can anyone help me get to shock level? I am using 12.5% liquid chlorine. Am I right like I should never let the FC fall below 8? Thank you so much for your time. I love this forum.

[BigDave]

Right, according to Ben's Best Guess Chart (http://www.poolsolutions.com/gd/best-guess-swimming-pool-chlorine-chart.html), with a CYA of 120 you'll need to keep the FC between 8 and 15 - never below 8, shock level is 25. About 6 gallons of 12.5% should get you there.

[ghostcat]

Thank you very much!