I have a 55 gal tank and thought go big or go home so i went with the 300 watt heater and im glad i did 250w would have been enough my heater sits close to the middle right next to the super aqua power head pump so i know my tanks water is being heated through out and this is confirmed with the hde lcd digital fish tank aquarium thermometer i have attached to the back corner of the tank

I have the top inch of the heater out of the water so if need be i can adjust the temp without getting my fingers wet the heat adjusting knob is a little tricky to twist but ive only had to do that when i first got it the temp fluctuates maybe 12 a degree the various fish i have calls for temp ranges of 68 82 so i think we are good at 74

5i timed how long the heater stays on and off and its about 15 minutes either way so 50 usage good deal