Thanks. I'll try the food dye, and I have a jabsaw for cutting drywall, I imagine that might work well for cutting out foam.
And yes, it is not in the equipment bay - there was a leak there at the pressure switch- but I fixed that.
The foam on the opposite side of the tub is wet, and it looks like the leak is pretty old, as it is covered in a black mold, and the inside of the side cover is coated in black mold. This is on another side as well, but the highest point of the mold/evidence of leak is on the side opposite the equipment bay.
I am thinking the leak is probably near one of the jets, so I need to dig down until I get to the ports on the side of the tub. As far as tipping the tub, I don't imagine that is an option when the tub is full of water, or even when it is empty -isn't it pretty heavy?