Forgive me because I'm going to get pedantic about LANs. Best to keep things precise.
With an old router try the IP range 192.168.0.2-192.168.0.255
You can't use 255, you can only go up to 254.
I am also suspect that your Nighthawk router is too fancy for the old adapter. The adapter comes from an era when LANs run at 100Mbps or 10mbps and using IPV4 protocols. Your Nighthawk router does fancy things to support IPV6 and convert it back to IPV4 and support 1Gbps LAN speeds.
This isn't what really happens. IPv4 and IPv6 run independently in parallel as a "dual stack."
I believe you can also change the DHCP subnet range from 192.168.1.xxx to 192.168.0.1 - but this will result in your presently connected wireless devices to not have router access until you re-pair them to the router.
Actually, it will result in all devices losing access, not just the wireless ones. All network devices would need rebooting to find the new network via DHCP. They don't get "paired" like Bluetooth devices.
Any chance you'd be willing to set a static IP for ScreenLogic? This will lock a specific IP address to Screen Logic.
This is not a static IP address. This is a reserved DHCP address. A static address is set on the device; a reservation is set on the router. You can try a reservation if the device's MAC address is known, but if the previous owner set a static address on it, and you can't clear that static address, you're stuck.
It's also possible the previous owner used an entirely different network number, not in the 192.168.x.x range, which is stuck in the protocol adapter. Guessing might take a while, but you can look at the ranges shown in
this Wikipedia article. If the previous owner can be contacted, it would be easier to ask.
I wish I had this device to play with, but I will put forward a couple of ideas. (1) We all know Pentair manuals suck. (2) Who ever heard of a device which needs 3 presses of the paperclip reset button? I would try a long paperclip press, maybe 10 seconds, and see if that gets anywhere. I have more unbent paperclips in my house than bent ones.