One of the first things I always do when I arrive is set the hot tub to the temperature that I want it to be, because even if I’m not planning to get into the tub that night it will take a long time to heat up.
There are chemicals and testing strips in the cabinet by the wet bar on the lower level. There are also lots of beach towels there too.
When you leave, it’s important to turn the hot tub to the low power mode. Before leaving, I’ve also put in a bit of the chlorine to kill anything in the tub at the time and maybe keep bacteria low before the next group comes.