70 is way too cool for this species of snake. 70 is ok for a corn snake, but I still wouldnt even leave them that cool.

Your tank is massive. I would say you need to do some work ASAP to save this other BP before it too succumbs.

Buy a 28 quart sterilite tub, an Accurite thermometer/hygrometer from walmart.

Put the UTH on a thermostat, set it at 88-92 degrees. We want him to have a basking spot of AT LEAST 88 degrees.

The ambient air temps should be around 80-84. Humidity should be at 60%.

NEVER use pine, use aspen, or some other commonly used substrate like eco-earth or even newspaper.

Please, please do this. Read the caresheet and decide if it's worth it to continue following this one guys advice when it obviously isnt working.