I am running my 9010 on the bottom of the sump without an extension set. The problem is that it keeps moving around and won't stay in one spot. If I maintain the proper water level will the skimmer perform correctly by replacing the slotted cover with aspirator cover 9010.200 and suction cups or do I need the complete extension set? The reason I ask is because I noticed the aspirator cover in the extension kit does not have slots.