My floor looks a lot like that. I scraped glue and all the gray glue residue-- I evened it up a lot before I started putting down my hydro turf. I was worried that the hydro might not stick to the slightly uneven glue/floor residue that was still left. ha ha. I had to rip out a bit of finished hydro I had put down. It was almost impossible to rip back out. So, scrape it clean and even and shopvac the dust. Your hydro will stick fine.

