Closing-antifreeze and chlorinator in return lines

[romeo17]

Closing an inground pool for first time. Last year I hired pool company and remember they installed duck valves on returns and pushed antifreeze through return lines but I don't remember how they did it. After the sand filter, the line goes through heat pump and then chlorinator and then returning into pool.
I did some research and learned anti freeze shouldn't go into chlorinator. I vaguely remember pool guys used heat pump line to add antifreeze to returns, but I might be wrong. Since I haven't added chlorine pucks in chlorinator for a month now, I am wondering if it would be safe to put chlorinator knob to 0 (zero) and pass antifreeze through chlorinator into returns.
Below is the setup and pictures of pump and setup.
One main drain, one skimmer, two returns, sand filter, chlorinator

 

[wireform]

Not sure what else you have there cuz some equipment is missing in view. I would assume the chlorinator is after the HP. With duck plugs you would blow from the equipment pad out to the pool and get full air before you stop. You then cap it off with a threaded cap. For extra insurance pour the antifreeze in the last place before the pool. On the heat pump open both unions and let drain. Not sure with this model if there's anything else that needs to be opened and drained. Don't forget the filter, pump and skimmer lines. Also if there's a main drain it'll need air lock.

 

[romeo17]

Thanks for your reply. Yes, chlorinator is after the HP and last place before pool. My main question was if chlorinator hasn't been not used for a month is it safe to pass antifreeze through it, after the HP, since I'll be opening heat pump unions anyways. I am not confident of opening chlorinator connection