I got a new 28 gallon marineland euro aqauarium. I need a heater and was wondering how many watts i need. I plan to buy a marineland stealth pro heater I was thinking 100 watts because it says ideal for up to 30 gallons. I was also looking at the marineland visitherm heaters. Which one is best? And one thing that i found strange is the stealthpro 100 says 30g while the visitherm 100 says 29g. So which one is better and why, and is the 100 watt best?