I would not use these tabs in a system that has had trichlor. After reviewing the data on the page these tabs may not work in a trichlor feeder. The feeders for these tabs work by allowing the tab to disolve from the bottom on a defuser plate. Trichlor tabs are imersed in water and slowly disolve from all sides. This product would disolve too rapidly in a trichlor feeder. I would not recomend using these tabs in a trichlor feeder.
Steve