OH boy.....which means as a newbie I will probably never figure this out! I dont want to mess with what it is doing right now because quite honestly, I dont know what it's doing. I just want control of the flow and to get the water right. All that other stuff can come in time.
Are you able to contact the previous owner? If so, this can be very easy to get things under control. If you cannot reach them, it will be a bit of a process, but I'd be willing to help you out. I'm the guy who wrote the 8-part Apex Programming Tutorial series here on Reef2Reef:
https://www.reef2reef.com/ams/neptune-apex-programming-tutorials-part-1.685/
If you can't get the login info from the previous owner, this would be the process to recover:
1. Inventory all the Apex modules. This would entail following each cable plugged into the Apex and EnergyBar to see what is connected and where.
2. Factory reset the Apex. This will wipe out all its programming, but would let you connect in to set it up from scratch.
3. Program all the basics....Heater control, return pump, powerheads, etc.
4. Program any additional features based on which modules are connected.
Once the Apex is online and linked to Fusion, you can grant remote access to it, allowing me or someone else you choose to connect to assist in programming or troubleshooting. Once it's set up, you can then remove the additional remote access.