Why is it bad for power head suck air

[Tmaxwu]

Sorry if this has been asked, I did search around and didn’t quite see this answered.Y nero3 power head is sucking in air and creating vortexes regularly. I know to place it lower to stop this. My question is why is it bad? Right now it’s positioned perfectly to blow over my few sps frags. I don’t want to lower it. Thx!

 

[blaxsun]

Pumps are designed to operate in liquid and not air environments. They'll prematurely wear or burn themselves out if not completely immersed.