I just replaced the big O-ring gasket on my Hayward ec-75 Perflex filter. The leaks have stopped but now my water flow slows down after an hour or so (checking the strainer basket on pump) I have to stop the pump (newer Hayward) and restart which usually works for another hour or so. Is there anything on the filter that I could have affected that woud cause this behavior?

What is curious is if I open the filter drain valve when its running low the water flow spikes throught the pump and flows like it used to. The filter is clean (I opened and cleaned when chnaged O-ring). Is there anything on the filter that would cause this?