I have 2 10 gallon tanks and they have a UTH under each of them, but the Temps on the Hot side only reach 80-82 degrees??? Any idea how to fix? i have tried putting a sheet over the screens on top but that didn't help any... The UTH's i bought do not have temp gauges... what should i do???
Any good ideas?

All advice taken in consideration!!!
Very Respectfully,
Matt