I have a large 500 gallon cube that coraline algae has left little tiny scratches in the acrylic. The tank is 6ft long and 5 ft deep. I have tried orbital polisher with different products. It is taking way to long to make any progress as I have live stock in 4 different tanks through out my house. I heard you can flame polish scratches away, how safe is it and how do you do it? thanks guys and gals.