My lanai seems to accumulate dirt and mud. Some of it is from my wife's potted plants and I guess some of it is just tree dirt that filters down through the screen. If I hose it down, the water pools up along the edges of the screen walls. I'm thinking about something like a carpet cleaner that shoots water down, and then sucks it back up into a tank. But all the ones I have found say not to use it on hard surfaces because the metal edges would scratch the concrete, or the concrete would ruin the cleaner. I only need to clean it about twice a year, so I don't want to but a $3k hoover. I would like something I can rent, or something more economical to buy. Any ideas?