That kit is good. A few yrs back my son got some sand grains in my mag float & turned my acrylic tank into an etch-a-sketch. I used a similar kit and the arcylic fines didnt hurt a single sps. I collected the debris with a filter sock.
Keep in mind it takes some time & muscle. Took me 30min for each 12"x12" section (8 hours for my 75g). My neighbors told me they heard some bezerk foul mouth guy cursing all night. & you have to do an entire panel, not just 1 scratch or part of the front pane.
You make a better kit with 6 grains of sand paper: like 600, 800, 1000, 1200, 1400?, 1500 & drain the tank to 3 inches & use a cordless drill with a circular sand paper holder like for buffing out headlights. Just keep it wet at all times & be done in a fraction if the time.
Good luck!
I was just looking around Marine Depot and found this product. Its getting good reviews, on removing scratches on your reef tanks. You can do it while its wet ! Don't have to drain the tank.....
Lifegard Aquatics Acrylic Scratch Removal Kit 72000.