Where you live you don`t need much in the way of a heater.
Unless you keep your air conditioner in the lower 60 range, 1-3 watts per gallon would do just fine.
Keep in mind, fish tolerate a bit of colder water considerably better than overly hot.
Can`t recommend a brand of heater, since I hardly ever have one in my tank.
I have a really cheap-o 50 watt that has no adjustment on it that I put in when we get a cold snap.
Our cold weather drops the in house temperature to the mid 60 range(too cheap to turn on the heater).
The cheap-o heater has never let the tank drop below 75 and I never worry about the water getting too hot.