Ok I fixed the problem. As suprair mentioned the is small gauge wire from the distribution bus to the circuit breaker. This is the wire
I replaced both circuit breakers to 4 gauge. Here is a pic after I did the first one (wire loop on left):
I thought for sure this had to be the problem but still same result - when I cranked the volume the HU turned off. I did some more troubleshooting and figured it had to be the HU ground. From the factory it is run to the cockpit amp ground. Reran a good ground to the HU and problem solved. This is not a 10k custom system but it sure does put the factory system to shame. A few pics:
The factory sub is disconnected. I plan on having the new box rhino lined and then covered with seadeck to match the factory look inside.