I have not yet had time to shock the pool fully since I started working with this pool about a week ago. I finally had time to crank it up and after measuring 5.5ppm I checked pool calculator and came up with 315oz of 6% bleach to raise this to a shock level of around 15 - this assumed a pool with around 16000 gallons. The bleach I'm using is a Food Lion generic of some type that claims 6%. I decided to dump a full 364oz of bleach in since I was not 100% positive of my CYA measurement and I was OK if the shock was a little higher. The predicted increase was 11ppm for a total of 16.5ppm expected.
Two hours after loading the pool with the bleach (loaded at 10:30pm, collected sample at 12:45am, finished up with tests around 1:10am) I had a starting OCLT value of 19.5ppm FC. Looking into this further I figured out that in order to get the 14ppm increase in FC I needed to have a pool of about 13000 gallons - or bleach that was stronger than 6%.
Given the fact that the pool is roughly 16x32 with a shallow depth of 3' and a deep end depth of 5.75', and the fact that the pool has sloping sides that get narrower as the pool gets deeper, and the pool also has rounded corners but is otherwise rectangular I had expected closer to 15500 gallons or 16000 gallons. (I'll try to upload a picture soon).
Oh as for the OCLT - not great.
Ph: 8? (> 7.8 < 8.2) (Before adding the Bleach this was 7.5 - I suspect false result due to high FC)
CYA: 45? (Tested indoors at night by flourescent light)
TA: Not tested, last test 175, test strips (which have been fairly accurate) shows around 180.
CH: Not tested, last test 350 - no fill water or rain since, minimal evaporation.
9am results (no sun on pool at 9am)
Ph: Not Tested, Test Strip shows 8.2 - same as last night, high FC false expected
CYA: Not Tested - no change in this expected
TA: Not tested, Test Strip shows 180'ish still
CH: Not Tested see above.
So I've lost 1.5ppm of FC overnight. <sigh> Guess I have to keep shocking. At my CYA level I was going to shoot for 16ppm or a slight overshoot. The pool is 5 mins from my house where I am working from home today. However I'm busy off and on all day without flexibility to drive back and forth willy nilly. I figured I'd check again sometime around lunch and add more bleach if needed then and again this evening. My expectation is that over the day I will lose another 1.5ppm in Organics consumption, and 3-5ppm in Sunlight losses. So I am expecting to need to raise the FC back up around 1pm by 3-5ppm keeping it around 19-20ppm mid-day and then expecting a night measurement of around 16ppm.
Is this a good plan?