I am not knowledgeable about vinyl pool liners, but here is a question pertaining to a robot in your situation. I have a Maytronics M500. I bought it for the third brush it has midway between the front and rear suction slots. It also does an excellent job at--and even slightly above--the waterline. [Side note: I had planned for an M400 which lacks the remote control feature but upgraded to the M500 based on Marina Pool & Spa's pricing. The M500 was still a waste. I never use the iPhone app and always use the same program, so the M400 is a better value.] Back to my question you. I am impressed at how much "heavy" stuff the robot picks up. My pool is plastered with that stuff with millions of little gravel bits in it, and some break loose--or may be broken loose by my 3-brush cleaner. That makes me wonder about wear and tear on your bumpy vinyl bottom. Someone here probably knows, but it seems like that might put extra wear on the high spots. The very thing that makes the M400/500 so effective could be harmful to your pool bottom. Just a thought. If no one here replies, you might try contacting Maytronics with that question. If not a problem, the M400 will clean the bottom and sides of your pool very effectively.