Im new to working at a pool store and I have a customer with a 25,000 IG VINYL POOL. Lately almost everytime he vacuums he says his vacuum plate will pop off at random times like there is air getting in the lines. He says he will put it back on and will work again fine after he re primes it. He has a brand new triangle vacuum, hose and vacuum plate. What could this be. He says sometimes it could happen every 10 mins and sometimes doesnt happen at all.