HOG1x Hang-On-Glass Upflow Algae Scrubber ATS Aquarium Filter Turf Saltwater Replaces Chaeto Reactor Protein Skimmer Sponge Canister Pellets Zeo Waterchange Probiotic Removes nuisance algae, nitrate and phosphate from aquariums Can't overflow onto your floor and because it is always under water The extra LEDs (compared to the hog1) work especially well In high-nutrient tanks, or in tanks with lots of nuisance algae "It cured my cyano problem in about 3 weeks" -- "flypenfly" on the scrubber site