Sucking Noise

[waterbear]

Every so often the return makes a sucking noise. There is a little whirlpool at the time this happens.

Sue225, this whirlpool forms about a foot in front of the return, correct?

This is caused by water coming out of a return with very high velocity and the return is not breaking the water surface. I have seen this happen more than once and it even happens when I take my pressure cleaner off it's port and put the eyeball in. (it's a very small eyeball to maintain the proper operation of my water features, which share a separate pump with my cleaner. If I put in a bigger eyeball to reduce the pressure of water from the eyeball and increase the volume the sound and whirlpool effect stops. The sound is actually coming from the little whirlpool that forms.)

Having the return pointed to break the water surface can also stop this but then you will have quite a bit of water turbulence at the return. I suspect that the return has a very small eyeball in it or possibly some sort of obstruction if that is not the case...