Honestly I'd venture to guess most pool stores use a combination of an aglaecide, which isn't dependant as much on CYA to keep algae away, and Trichlor tablets which (a bunch, and an ever increasing amount) to allow a slow release of chemicals throughout the week. So yea, a rollercoaster of sorts, high when they leave, drifting towards too low when they arrive.
None of that accounts for swimmer loads, additional "accidents" in the pool, etc. That's why people typically complain about the "chlroine" smell, which is in fact ammonia, as the chlorine combines with nasty stuff, and the stronger the smell...the more nasty that's in there. Most people just accept that stinky water, burning eyes is how Chlorine pools are.
I swear I get crazy looks when I bend over a pool, scoop some water in my hand, and bring it up to my nose and smell it, then make a note whether I think it's fairly clean or not, but once you start understanding the chemistry, it makes sense to us here on the forum.
Great looking pool btw!