Inputs/Ideas on insulating dump bay compartment??

Hey gang,
My Damon has done great in well below freezing temps this week and my tank compartment is insulated and heated with the furnace.
Problem is the driver side of the compartment where the dump is has that cheap plastic bottom with no insulation and that area is the low side of my fresh tank and where the feed line to pump is. With the temps in the teens, that caused that area to freeze and froze the pump input line. I've put a small heater in the bay and starting to get a little water flow as it thaws. Tanks didn't freeze.

Question is: what is a good way to insulate the bottom of the dump area to help hold the heat.

I've thought about getting electric in the compartment and adding a small heater to place in the bottom to use when we are in temps like this, but would like to see if I can find a permanent solution that will allow the furnace to keep things working normal.

Can add pics if that would help.

Thanks in advance for ideas.