Items bouncing on top of hoppers

When an item lands on top of a hopper and cannot go in it, it bounces around. This is very frustrating; I have built an item organizing system that involves items running over filled hoppers in water with specific items inside them. When the item lands on a hopper and cannot go in, it bounces off of it and sometimes over other hoppers which is a huge problem for my organizing system! If you could make the top of the hopper hit box solid or something, that would be great; just do anything to make items not bounce on the hoppers please. Thank you.