Sure you haven't got air getting into filter through pipe fittings, filter should shut of every 12 hours I think it is,, to realise air from filter,, might be every 24 hours
Set your filter up like I said and you will have good water quality and your filter will only need cleaning every 20 days ( depending on how you have stocked your tank)
I have removed the 2 way outlet nozzle from my filters and replaced with a 15 mm push fit elbow, this increases the power of the water coming out of the outlet