I never could keep my pool clean - I always drained it, scrubbed the bottom and refilled it. I never thought I would find a pool vacuum worth a poop that would actually clean!... but I was amazed by this inexpensive wonder machine! it hooks up to the pump RETURN and moves one way for a certain amount of seconds, pauses, then reverses the other way. to clean it, is a piece of cake as well! pull it up, flip it over, unclip the 4 clips to removed the cover. the cover has the screen in it that just snaps in. no tools required to clean the vacuum!! put the screen off, shake it, get the debri off, then pop it back into the cover, clip the cover back on and lower it back into the water. ta-da! miracles! also, the hose comes in sections. I have an 18' round pool and used all but 1 section. each section is about 4 feet long so I'm guessing it would cover up to a 20 foot pool well. The ONLY issue I have had once, is that the vacuum moved in a pattern that sort of twisted/tangled the hose and then he couldn't move around much. I figured out the best way is to completely straighten out the hose and get all kinks out. The wheels do not power the movement - GREAT! - so they cannot dig into your liner!!! the returned water flows through the unit and that is how it is powered. This is going to save me so much maintnence and I will replace it when it wears out.