I had a Dino flow 350. I totally agree. The magnet underneath ( separate motor slide on bottom ) spin the impeller. The magnet was on the outside. The impeller was on the inside. There was a box and it was filled with the angel hair or whatever and the hose was connected to the box so as the impeller spun, it would suck the water from the tank in through into the box through the box and then it will rise and then flow out best aquarium filter design. Wish I could find one.
how about the Dino flow that had the little stick with the closed cup on the end that you would put around the inlet hose so you would fill it with water and it would actually hold the suction then you would put it into the box so it acted as a siphon as the water spilled out it would send more water back into the box like gravity, fed, or whatever dynaflow made great filters. Of course these were from the 70’s
Ps. Spelling of dynaflow. I was using voice to text. Lol