I'm seeing a huge discrepancy on actual wattage needed for a specific tank size between the Finnex Ti heaters and the Jagers. Jager list 150w as suitable for 53-79g and their 300w is for 159-264g. Finnex lists their 300w for 40-80g and their 800w for 140-265g. Do I follow their recommendations or is there a better rule of thumb to follow!?! I've been using a Jager 150w as a main and a Cobalt NeoTherm 100w as a back up though both come on at the same time.