Overshot my numbers

[BlueEye14]

Second season of managing this pool after moving into a new house. Almost didn't look at the house because it had this pool, but it's become somewhat of a pet project. With the help of a very kind neighbor and being introduced to this site I sailed through last year, but have been having some unexpected trouble after opening this year. I have a pool guy who helps open and close, but for the most part am trying to deal with the day to day myself as much as possible. Water looks pristine.
8000gal (to my best guesstimate), SWG, vinyl lining
pH 7.5
FC 32.5
CC 0.5
CYA 100
TA 80
CH 100
Salt 3200

I had hoped my first post would be solely about trying to optimize my pump run time with the SWG (currently 8 hours at 50% - a mix of what my pool guy last year initially suggested and what ultimately worked to keep the levels right), but an incident last week with a pretty significant leak from the inlet to the pump had me worried I'd have to leave the pump off as much as 3 days and I added too much shock to prevent algae. Story short, issue was mostly corrected (still a slow ooze, but that's another question), but I clearly overshot the chlorine levels.
1) Is there anything I should be or could be doing to bring down the FC (I know the high CYA doesn't help this)? Can I be lowering my SWG on percentage? If so, for how long? For what it's worth, I've been in the pool and the elevated chlorine hasn't been bothersome.
2) Despite this, is it really necessary to replace water to bring the CYA down 10 (no idea how the level got to where it is, I used poolmath to calculate moving it from 0 to 70 when I opened the pool)? I'm worried about overshooting in the other direction.

Salt is at the desired level. Pool has a small fountain and a step jet that aerates as it returns so I know the pH will come up without much intervention.

Appreciate your thoughts.
Thanks.

 

[HermanTX]

Welcome to TFP.
What test kit do you use to obtain your test values?
Are you sure it is CYA 100 and not higher? Have you tried the dilution test?
CYA can only increase if you add stabilizer. That can be 100% stabilizer or via use of pucks which has stabilizer in it in addition to chlorine. Some granular shock may have stabilizer but mainly calcium but your CH is not that high.

Per our SLAM process, FC is 40% of CYA and it is safe to swim. So if your CYA is 100 or higher then the 32ppm FC is Ok to swim.
Since you have 8000 gal pool is it easy to lower 20-25% to lower CYA assuming it is 100?
In PM app, there is a section on Effects of Adding that you can select SWG and then input % output and pump run time to get predicted FC output over a 24 hr period. you need to select the specific SWCG you have.

You can turn off or turn down the % on the SWCG and let the UV and bather load consume the FC. Just test daily to check the value.

 

[BlueEye14]

Thanks for the response.

Test kit is TFTestkits TF-100
I suppose the CYA could be higher, but am not entirely convinced of that. I've still had an internal struggle of judging when I truly feel I can't see that dot at the bottom of the beaker anymore and 100 felt right this time.
For the CYA I'm surprised with how high it shot up because the volume I added was the amount calculated to raise the level to 70.
I was not familiar with the dilution test until looking it up just now.
CYA was increased with 100% stabilizer and chlorine is 10% bleach.

'Since you have 8000 gal pool is it easy to lower 20-25% to lower CYA assuming it is 100?' - by this you mean drain the pool and replace the water? Not particularly difficult to do this, but as I mentioned I'm worried about overshooting in the other direction.

 

[HermanTX]

'Since you have 8000 gal pool is it easy to lower 20-25% to lower CYA assuming it is 100?' - by this you mean drain the pool and replace the water? Not particularly difficult to do this, but as I mentioned I'm worried about overshooting in the other direction.

Do another test of CYA in the morning and if it is still 100 then do a dilution test to fine tune the number.
Draining is a % of CYA. So a 25% drain will lower CYA by 25%. Thus the need to know what the CYA number is.
You can manage a SWCG with 100 CYA but it takes a higher FC, Take advantage of any rainstorm by draining some and let the rain fill it back up. it is a slower process but will get it down over time.