Installed a new c4025 cartridge filter in place of a sand filter last night. Today was looking for any leaks”nun” and I can open the bleeder valve on top of it about half way and nothing but air is coming out? I have 10 psi on the gauge. I have some bubbles in the pump and some out the jets but small amount always been this way. I can leave the valve open for awhile and it’s always air. I can open it more then the water starts?