Commercial Hot tub topside controllers

Hello, I'm a noob here and not sure I have even brought this question to the right forum. I am currently making an arduino hottub controller to retrofit my old Jacuuzi up to a usable standard as plenty of people before me have done.
My question is around the waterproof topside controllers found on newer model hot tubs and if anyone has worked out how to repurpose something like this to connect with arduino. I am sure it has been done but so far havent found anyone online talking about it.

There are many different types of communication between the control panel and the drive board, so it may be easier to try to get the service manual with the schematic diagram, or reverse engineer a working panel to monitor the way the communication was implemented. This type of posting is usually related to "hacking".

Hot Tub Controller Hack part 1

There are only three things to worry about! Safety! Safety! Safety! You probably cannot find anybody talking about because they wanted to stay around to do another project. If you are not experienced in mains power, safety, isolation and control just purchased a new controller and be around for a long time.