I have my guppy fry in a 10 gallon tank currently... I have a petco heater in there, I'm not sure off hand the wattage or what it is ranked for, I originally had it in the 5 gallon. I don't think it is working properly for the 10 gallon as temps are reading between 74-76 and I have it turned all the way up in hopes of getting 80 degrees. (There is no choice, just +/-). I have a new hydror heater 100W that says minimum 14, maximum 26. Is there any reason I couldn't use this in the 10 gallon? I'm assuming since it says "minimum" of 14, there is a reason for that... but the one I have in there is keeping it too cold, and my local fish store is over an hour away where I could get a decent heater. Thanks!