So i recently got a linear piston air pump from my grandpa. finally got it hooked up to all the sponges today and turned it on. At first, it works perfectly, i even had to open a few bleed offs. i come back ten or so minutes later and all of them have lost a significant amount of pressure, a few of them had even stopped completely. I checked the taps, all of them were on full blast. I checked all the joints in my pvc, the hose from the pump to pvc, etc. I felt the pump and it was pretty warm, but not burning me by any means. I turned the pump off and then back on about ten minutes later, and the exact same thing happened, I'm thinking it has something to do with it's warming up. But i thought that was something it was expected to do? What am i supposed to do? any suggestions?