I have an 80G cube, 100G total volume, and I'm looking at getting the Helio PTC dual heater for the tank. Normally I would get the heater rated where the tank volume is at the top of the recommended size so the heater could never cook the tank. In this case the 2x200W is rated for 50-100G. However if I trust in the tech and the the ceramic chip limiter won't let it ever overheat, I'm wonder if going with the 2x350W rated for 100-170G would be more efficient. Thoughts?