Im not sure what the scratchproof acrylic pannels will cost, and I dont personaly construct the fiber glass tanks, but I know he uses many different weaves of fiberglass and many different bonding agents which probably dosent help you at all...

I was thinking of a large suspended sump with a water level limiting, open stand pipe drain to prevent overflow in case an electronic selinoid ball valve fails, the ball valve will work on an open closed cycle, and the pump will move water continusly, probably a large ball valve of 4" or more.