I think you'll find most folks run without it. If I understand an earlier thread correctly, the foam cover was actually a later add on to the pump. Some people were experiencing livestock losses due to smaller fish etc. getting sucked into the pump, so EcoTech came up with the foam. So if you have smaller critters in danger of being sucked in, use the foam and deal with the requirement to clean it often. If not, run without the foam and have one less maintenance issue to worry about.