I removed the remaining paneling and valance.
There wasn't any insulation where the foundation is, or between the two stories. I built out the wood frame and added 1.5" foam board insulation to the foundation. Now everything is flush and I have very deep window wells.
The floor is 3/4" plywood on 2X4 sleepers. It doesn't provide much thermal protection and I didn't think it would support the tank. I had the tiles tested and they are asbestos containing so I couldn't rip the entire floor out. I sealed the entire area and cut out the floor where the tank would be.
In the picture you can see the new water line run. The other hole is where I ran some Cat5e for the aquarium controller to hook up to the internet. You might also noticed the paint color, yes that is RL Spa Blue. It makes you just want to relax, maybe even do some Yoga. The portion that will be behind the book cases didn't get hit with the brush yet.