I wish it was 80 degrees here..it would feel like winter. I have been watching my tanks and while 3 of them get direct sun for 1/2 the day I havent seen any temp problems, maybe I am just lucky or my glass is self cooling..
What are the temps?
Scott you have been here long enough to know we need more info to answer questions, your dumping 65 degree water into what 70 degree water 75, maybe 80??
If the temps are getting to high go with the methods in that other thread, make sure you keep the water well oxygenated and increase aggitation at the surface. These will allow the tank to disperse heat faster.
Maybe a better question is at what water temp do you really need to start being concerned?