hey Mike
The divider is just a tight fitting piece I cut, but there is a secret.
In 55 gallon tanks there is a plastic piece in the middle of the tank that helps keep the tank from swelling in the center when filled with water.
I drilled two holes through this piece down into the divider and added two screws to help keep it secure. One thing though. I had to notch the top of the divider because there is a piece in the dead center of the plastic piece that protrudes downward.
If you look at a 55 gallon tank you will see what I mean.
The lids are plywood cut to , I think, 13" x 24" (half the tank)
I cut out a round hole for the dome light and then stapled nylon screen to keep the snakes from escaping. I drilled several rows of holes on each side of the lid for circulation.
Add handles for easy lifting.
To make the lids secure I add strips of board to the bottom of the lid. These are cut to the same dimension as the inside of the aquarium ( 12 1/2" I think)
These are fastened to the underside of the lid approximately 3/4 of an inch from each end. They need to be a tight fit. When you place the lid down on the aquarium it needs to be a fairly tight fit.
I have never had a snake escape from a tank with these lids.
Not very technical but I use bent nails to hold the dome light in place.
You will see the nails in one of the pics. I just place the dome light in position and turn the nails towards the dome and they hold perfectly.
.
.
.
.