Chemicals can be added consecutively under normal conditions, but when working with muriatic acid, you may want to add at least one hour apart. If you are an early riser, I would set the timer to go off at 6 a.m. or 6:30 a.m. for two hours before the pump shuts down, therefore allowing plenty of time for chemicals to mix. The MA can be added in the sun, but the liquid chlorine should be added early morning out of the sun so your levels will go up and then come down overnight. Of course, you can add the chemicals at night as well, just make sure that they mix for at least an hour, preferably two hours before shutting off the pump.
Then allow pool to bake in the sun for a few hours and have pump turn back on at 12 p.m. until 6 p.m. for another 6 hours. A total of 8 hours should be sufficient for your pool. My pool is set for 6 hours as sometimes it runs manually in the morning while I vacuum or test for a few extra hours.
PS: I see you have a VSP, so if you keep on low for most of the day, then really no need to change the cycle. My pump (2HP), would consume $120 of electricity per pump as it is a single speed. At 6 hours per day, I am at 50% of the cost. I would literally leave on for 3 hours if the heat pump was not in question.
