Thats a big change, good for you, is 80 the temp you are aiming for?
An idea, in my hood (aquarium not location), I have a fan that blows in and one that blows out to move the air across the entire length on the tank. I even went as far as to close off the back of the hood to improve the efficiency of the air flow. You could try another fan on the other end blowing in the same direction and see if that helps a bit more. Not sure this would work but for another $10 it might be worth trying. Besides, if it doesn't work you will have a backup fan...
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110 Gallon FOWLR, 25 Gallon sump/refugium.