Heres some good advice.....Get rid of the pump!!!!!!!!! :yes: The pump is more than likely cooling itself using your tank water, so that's why your seeing the rise in temp though.....82 really isn't that bad, but the key is to keep the temp steady and not having it all over the place........
Since you have a wet/dry I would suggest drilling the wet dry for a bulkhead and running an external pump.....