I have 3 toilets with extremely sticky Mansfield Flush Valves on 160 Toilets after 6 years.

I read somewhere that this is caused by suction and bad gaskets after use of chlorine in the tanks. (My wife does that before we leave on trips due to growth in the tanks) ?

1. Should I replace the whole Valve or just the Gasket ?
2. If replacing the parts, Should I use
A. Fludimaster
B. BLUESOURCE HYDROKIT TOILET REPAIR WITH DUAL FLUSH CONVERTER
C. Replacement Mansfield mechanisms ?
D. Other recommendations.

Thanks for your recommendations.