add rola chem to feed acid

Good morning,

I have a t-cell that runs on a time clock. The timer is set to run WITHIN my intelliflo runtime to protect the heater from back flow when pump stops. The check valve between heater and cell is 20 years old and may or may NOT work. I've been wanting to add a rola-chem to feed acid. I can't be feeding acid while generating chlorine, right?
 
Combing chlorine and acid is not recommended.