AquaBlade-P replacement blades were custom designed just for cleaning acrylic aquariums. Continuum Aquatics uses a special self-lubricating plastic that is softer than acrylic and will not scratch! Changing the blades out only takes a few seconds and there is nothing better than a fresh new blade for cleaning stubborn coralline algae or other deposits that may have formed on your glass. The blades are made to endure repetitive cleanings but eventually, all scrapers will become dull and ineffective. When that happens just snap in a new blade!