Pumps may have small crevices and hidden cavities that make drying out difficult and unreliably. It's best to have 4 pumps, 4 heaters and 4 tanks for TTM so that you don't have to struggle with sterilizing anything during the process.
After use I would wash the tanks and let them dry out well. The pumps and heaters I would run either in a bucket with bleach for a day or in hot water (50°C to 60°C) for a minimum of 2 hours and then dry them.
After the fish are transferred out it should actually even be enough to just crank up the heat in the TTM tank to about 50°C for a couple of hours to kill all Cryptocaryon stages, as Cryptocaryon stages won't survive exposure to temperatures above 40°C for at least on hour. The additional time and temperature will make sure that every spot in the tank is properly treated.
You just need to make sure to top-up the water level above the level you had while fish were in the tank. This works of course best with acrylic tanks due to their thermal insolation properties. With this method you could even re-use the water for another tank or TTM step as it is also sterilized in regards to Cryptocaryon stages.
This is the way I plan to do it when cleaning up my fish.