I usually spend my time on the forum during the week, but since I took off the first half I spent that time either in the pool or doing nothing
After all the cleaning and food prep was done for my family visiting on Monday.
Hopefully everything went smoothly. As for the ladder, We dug out a spot where the base would touch and put in half of a paver to support the legs and base. So in total we have 1/2 a paver used to support the base where the legs attach, 2 pavers to support the base of the ladder itself and one paver in front of the ladder to step on. I tried to get it as close to resting on the rail without putting much pressure on it. (the legs go straight down from the "platform.")
When I have people over I usually bump up the chlorine before and after. There were 6 of us swimming on Monday for about 3hours and everything went fine, I don't believe I added more than 1ppm extra, but my situation is different. The sun seems to burn off about 5.5ppm/day when it's this hot out. I believe I added about 6.5 ppm on Sunday night and back to the usual 5.5 before an intensely hot day on Monday night.
20+ people would scare me enough to get it close to shock value. Well maybe I would just double it. I target 7.5, even though 7 is my CYA level target. I think between 20 people and an unseasonably hot/sunny day, I would shoot for 14-15ppm (at my CYA level of 60). How did it work out for you?
How high is your alkalinity level? If your alk level is high I hear pH swings can occur. My TA was around 125, but I've been lowering pH w/ acid because of the aeration to keep it cool. I will test my alk again soon, it should be close to 100 now.
As for the timer, I've looked in to it as well. Unless you're going to hard wire the pump to a "permanent" timer, you won't be able to run the pump on high. (I've yet to find a "portable" timer that supports over 15 amps)
Since I only run the pump on high to clean, I've debated about getting a timer (and unhooking it while cleaning), but running the pump on low 24/7 hasn't been a problem.