My tank is built into a wall unit so is covered on all sides, except the front. This means the water temperature changes very slowly in relation to the room temperature. Because of the in-builtness (good word eh?) it is difficult to aim a fan over the water surface so, on the rare occasion our tank temp has risen too far (we manage to keep the room from getting over 30C even if we can only turn on the ceiling fan when the budgie is in his cage) we have added frozen 3L bottles and found this worked well enough for what we wanted. 
If any of you feel you are getting overheated as a result of this thread, I suggest, on the count of 3, you all turn your fans on full  :lol:  
 
1 
 
2 
 
3!!!! 
 
Ahhhh  8)