When using any restriction at the skimmer eg connecting a pool cleaner, I get considerable quantities of air passing through the system. This indicates a leak on the suction line. Additionally, the filter does not work very well. I believe dirty water is getting back into the pool in this condition. My question is: would one expect the air to create sand conditions which would allow dirty water to get through?
Without any air apparent in the system, the filter seems to work although I have not yet achieved a clean pool yet because of the above.