Ok, so I'm not sure if you have heard of them, or seen them or played with them, I haven't seen much going around about them. As soon as Jake from reef builders told me about them I was pretty intrigued. I finally got my hands on a couple today and OMG these things are incredible. The blast through algae and light coraline with very little to know effort. If you strap on the metal blade they absolutely erase very hard old coraline algae like its fresh. Very little effort required to use these things, and my god are these magnets strong. I picked up a long and a nano today. I am using them on glass, and not acrylic. If you have an acrylic tank I cant really speak on them, as I know there have been a couple issues, Tunze states that you need to run the small plastic blades and not the long fiberglass blades for acrylic. But I can tell you for glass, these things are incredible and surprisingly well priced. I will end my rant here lol