I'm not sure if this is just normal disturbance from the filter being turned off (I do large water changes and don't want the pump sucking air) or if the filter is showing signs of needing to be changed. It has taken longer and longer to clear the last few water changes (but it does clear) from less then 30 min to a few hours. I have "cleaned" the filter by swishing it around in old tank water but is all this cloudiness a sign that the filter needs changing?