sandb4jeep

Hi Folks, Recently inherited a 16x32 in ground pool. Opening it up two weeks ago, I was getting a leak at the handle of the mulitport valve on the sand filter. I replaced the spider gasket, but still had a leak, so I went on and purchased a new mulitport valve. Not sure of it's model, but the one I replaced was a Hayward sp711-13. I started noticing large amounts of air coming out of the return when I am vacuuming the pool. I recently replaced the gasket on the pump it's self, and by this I mean the door that opens up to empty out the debris basket. The air isn't as bad now, hardly noticeable when running in filter mode....but when I hook up the vacuum, it starts pulling air again. I'm not able to use the navigator at all, doesn't seem like enough suction to operate it. Any ideas of where else I could be getting air? I'm not losing any water, everything in the pump house seems dry. Any ideas of how to find the leak? Thanks in advance!