Well in beween the rain and the cold I got the tank ready to reinstall.
I took off the old foam and lightly sanded the affected areas and painted it.
It cam out better than I expected.
Now I do not plan to refoam and the tank has 6 flanges that I can use to attach to the sides of the coffin.
There is some space that I can use to place some starboard that way it stays in place and no wood to rot.
now what can I place under the tank to keep it off the bottom and hopefully let any water that does get in drain and dry out?