no, you most likely have a leak - ours does this (but it is 45 years old....). When its purging, the vac pump is running - when its coating, it seals off the vac pump and does its thang. But its leakier than a sieve, hence as coating 'progresses' it gets more pink. As our timer is broken, I judge the thickness by the plasma colour....... Yes, I'm trying to buy something more.....modern.