I have the heating issue on my frag system well in hand but it did get me thinking... Do dirty pumps create more heat? I always intend to clean my pumps (return pump, powerheads, skimmer) on a regular basis but the reality is that my goal of cleaning every 6 months usually ends up being every year. Even a brand new clean pump causes some heat AND that dirty pumps can reduce flow over time. I've also found out that older pump (Pondmaster's specifically) can give off more heat because they're less efficient. But does a dirty pump give off more heat? Bro-science leads me to believe me that they would because the spinning of the impeller is less efficient but that's just me thinking. What do y'all think? Does anyone have an instance where pump maintenance led to a reduction in heat?