I've set up a camera system with all the cameras hardwired to a router. When I plug the router into the clients regular network, the dhcp from the two routers cross over and create problems. The client network is 192.168.1xxx. The camera network is 192.168.0.xxx. What am I doing incorrectly?
You have two separate networks. You likely have two DHCP servers (one per router) and it's not being attached to the network correctly.
If you're goal is to segregate the cameras from the regular network, use a switch which is cable of doing VLAN's and separate them that way. This allows the cameras network connectivity, and then you can use the firewall to block traffic as needed to the new VLAN. This also helps to avoid duplicating DHCP configurations.
Currently, you need to make sure that the WAN port on the second router is plugged into a LAN port on the primary router. This should block the DHCP values from being broadcast to the primary network, while still offering DHCP addresses to the cameras. You can then use the second router to provide static IP's to the cameras. You won't be able to access systems behind the second router (when connected to the primary network) without also configuring appropriate NAT/Firewall rules.