I am a 17 year veteran of DIY pool maintenance and repair of my IG vinyl pool. I wanted to post a quick question regarding using wheeled vacuum heads on vinyl liner pools. I am interested in the Pro Vac 214 flexible unit with rotating handle and ball bearing, polyurethane wheels. I can't seem to find any specific info on why it's such a bad idea. I got to try one out last summer, and it was AWESOME.....any comments or info ?