When I put in the heat pump I suppose I should replace the 10 year old parts when I build the pipe system. Whats the deal with the off line chlorinator? I hadn't heard of that before. And who makes a good multiport valve for my de filter??? Thanks for the help.

18x36 inground pool
about 10 years old
I bought a new filter last year- fns plus 36
I am purchasing a heat pump
I will likely install it myself