Improving a 30 gal mud/musk/stinkpot turtle set up?

Recently a wild 3 stripe mud turtle was a guest in a tank I was trying to set up and I very much fell in love with the little thing. Sadly being wild she could not stay, but I do have a reptile store near by....

You see where this is going.

However the tank (pictured below) is not turtle perfect and I was hoping for help to make it so.

The issues are:

Heat light placement: right now it's just clipped to the side of the tank and requires the hood to be open.

Escaping: The hood being open and the 3d background means the wild turtle could climb out

HOB filter: I think I have this one (https://amzn.to/2Ou04GL) or the next size up. (the tube is hidden by the weird rock shape) it struggles to work with the water level it is at. Is there I way to fix that? increase the suction or get a better tube?

Smell: There was a bad smell I could not get rid of with the turtle, I researched later and found out muds do have defense response that releases a bad smell which would make sense. It apparently does not happen with captive raised turtles much, but how can I be sure that was the problem?

Amount: I know a 30 gallons is good for these types of turtle, but change on the amount that can be in one tank

Details on the current tank:

About 20-30 mosquito fish and maybe a few ghost shrimp in there

2 live java ferns and 2 fake plants in the tank and a bamboo stick in the filter

about 4 moss balls

been running for several months

Dimensions: 18Hx30Lx12W

Water depth: 1 foot