pump losing prime when i vacuum

[sigepcj8204]

My pump has been losing prime when I hook up my automatic cleaner or when I try to vacuum. I replaced some of the above ground piping from the skimmer as it was old and looked like a prime spot for an air leak. Even when I don't have a cleaner/vacuum in my pump basket will never fully fill with water, but it still moves enough water for my heater to turn on and run. The cleaner worked for about 15 minutes today which is a big increase over what I got before I fixed the pipes. Also my cleaner does have a bypass valve in the skimmer that allows for some water to come in not through the cleaner hose. Any suggestions on what to try next?

[Denniswiseman]

You have a suction side air leak, try the pump basket "O" ring and lubricate with silicon grease
When you vacuum it puts an extra load on your pump and any poor seals will suck in air