ok so the heater i got with my tank aparently lights up like its working but dosnt heat up lol. right now in my 20g sump (aprox 50% water volume) i have a 10-15 heater whitch keeps the 75g at 70f and i know thats not enough (had it laying around used it in a pinch) i was thinking of getting 2 15-30g heaters and leaveing the 10-15g heater in and useing all 3. they come preset to 78f and i know there is loss and sutch by the time it gets to the mt. will this be enough to keep my tank around 75-76 f? if not i was thinking of adding the 10-15g heater right into the tank cause its small and useing the other 2 in the sump. i dunno what do you guys think.