Based on the Power you state @120 V for the heater element works out to just under 12 amps so you need that switch to be 15amps. Main panel switch will need to carry amperage for the pump as well so you need to figure pump amperage and add that to the 12 for the heater and then round up. Pump switch is fine as I dont think the pump draws much but you need to find out how much the pump draws any way so we will know for sure. also keep in mind that you need to double the pump amperage rating for all affected switches since it is a motor. Also you have power connection points up stream of the switch so power will be available to parts of the system before the switch is flipped. having never wired a PID I would need the pinout info for the PID SRR and RTD to fully check out/verify wiring. Also there is not ground wiring wich I sometimes leave out for simplicity when sketching/aranging things but at this stage, since this will be flying in close proximity to/hooked up to metal and liquid it would be good to be working on a final draft of grounding as well.
Qualifications: Aircraft Mechanic for 12 years and FCC General Radio Operators license and Radar endorsement.
That said, although I always trust my own schematics but I am not infallible, and spend considerably longer reviewing my own work, and can see/verify all the parts, ratings,connection ect. more info would help.