The Tunze aren’t the most efficient design of propeller pumps and they are a pain to clean (can’t detach the pump from the controller) but they’ve been pretty reliable and they are paid for so I’ve been hesitant to replace them. The Panta Rhei pumps are easy to clean, I unplug the pump and put it in a tub of vinegar and let it sit for a few hours, a quick brushing and rinsing and they are ready to go back in. (I have a spare pump that’s pre cleaned that I swap out with the one soaking). You can tell a big difference in the tank turbidity right away. A more motivated person (than myself) would realize that keeping them clean with frequent cleanings would probably yield an overall growth increase. I figure I’m mimicking seasonal tidal changes by not cleaning my pumps, at least this is how I am justifying my laziness... which I subsequently justify to myself as “not wanting to interfere”. :D