I received a 38 gallon tank for Christmas, and I need to pick up the supplies to get it started. I'm wondering what would be a good heater for this tank. I found some Fluval "E" series that are pretty pricey, but the few reviews I've found seem to be decent. Fluval also makes an "M" series that is a bit cheaper. I'm just wondering if I can get some insight on what some good heaters/brands are, and what I should stay away from.