Review on Mag Float Scrape Scraper Blades Medium Fish & Aquatic Pets by Nuzhat Shaver

Scratches very well. Recently there was an outbreak of cyanobacteria. I got rid of it with the blue green stain remover as usual (great product btw) but it always leaves what I would call hard polyps on the glass. Even after death, cyanobacteria are a cause for concern. The magnetic float just glides over it, which is impressive considering how rough the brush is. The scraper attachment removes them in 1-3 passes. It's also great for the substrate/water boundary (although I'd stay away from that boundary if you're using fine gravel, sand, or other substrates that might scratch glass. It's easy to accidentally snag the blade) . He doesn't scratch. my glass, but I wasn't worried about what it would be. I wonder if those who scratched their "glass" have acrylic aquariums. DO NOT USE METAL ON ACRYLIC. However, they make acrylic blades. It doesn't compare to a well-made long-handled scraper when dealing with a lot of debris, but for regular cleaning it's the best. The longer you can keep your hands off the aquarium, the healthier it is.