Buy your caulk from the dealer. Mt TPO was manufactured by Alpha and I always use the Alpha caulk then no issues with the factory or roofing warranty. IMHO I like TPO a lot more than EPDM ( having had both). It is stronger, does not "sluff off" causing black streaks as bad...and can be patched better. Neither roofing materials should be treated with anything....neither material is designed with a need to be washed or treated. In the case of EPDM its life can be shortened by constant cleaning and treating. TPO is slippery when wet. If you do want to wash it use greased lightning a soft brush and water to rinse. DO NOT use any treatment as it will be like using grease on it.