Before the pump starts? (looking for lowest level before replenishment occurs)
After the pump turns off? (looking for the highest level at the end of the cycle)
Some other time?
As per the Pool Calculator, the FC with an SWG should be around 3. So, I see a problem with measuring 3 just after the pump stops - it'll get pretty low before it comes back on the next day.
In contrast, If my goal is three just before the pump comes on, it must be higher than necessary from the night before.
So, what's the best time to measure?
PS: Pump runs about 10 hours a day.