cleaning
You need to clean the uplift tube everytime you clean the filter. You need to clean the impeller every time also. Restrictions in those areas will drastically slow the flow rate and can make the unit noisy.
A filter brush set works best, but you can use a baby bottle brush from Walmart for the tubing and a toothbrush (new) on the impeller. The filter brush on a flexible line is best, IMO. Be sure to clean down inside the impeller well and dump that out, use a paper towel to wipe out the body of the filter while you have it empty.
If you clean the filter media every week, you might only need to clean the tubing every other week, but do try to clean the impeller when you do the media, particularly if it gets noisy. If you wait a long time in between cleanings, then do the tubing at a different time than when you are changing cartridges, as lot of bacteria is in that tubing and you can have a mini cycle if you clean it all at the same time if you tank is borderline overstocked.