Bubbles in pump basket?

[packerfan]

when I have my Jandy valve right in the middle splitting the skimmer and main drain inputs I get a lot of bubbles in the pump basket. If I close the main drain the bubbles will subside And clear right up. How would I go about troubleshooting and seeing if I have a problem with the main drain lines? Thanks for any input I can maintain a steady pressure in my DE filter but it doesn't stay totally clear when I have it half-and-half.

[mas985]

What is the filter pressure for each valve setting? Skimmer only, MD only and Both

[packerfan]

Pressure on my e 65 de filter with valve in middle is16psi.when just skimmer its15psi and just main drain its13psi.

[mas985]

When the valve is set at 100% skimmer, do the bubbles get worse?

When at 100% skimmer, check the skimmer to see if it is sucking in air from a vortex.

If so, it could be low water level or a stuck weir

If not, it might be a leak in the line