We would be happy to supply you with the names of several companies who make chemicals that will work in this cleaner. There are chemicals available that effectively remove solder paste at ambient temperatures while other chemicals require heat. As a rule, temperatures above 100 C should be avoided to prevent possible stencil damage. Removal of the solder paste is fast and easy. It depends on several factors such as the type of chemical used, the type of paste being removed, and the volume of parts being cleaned.
Some chemicals have higher loading capabilities than others do.
The most frequent wash-solution exchange would be weekly, with two or three months being average. It depends on the wash chemistry being used. Some chemical brands do not require rinsing. Other chemicals do require rinsing. It depends on your tap water quality.