Santa Monica Filtration HOG3 Saltwater Upflow Algae Scrubber with Strings & Green Grabber Textures Best for saltwater, removes ammonia, nitrite, nitrate, phosphate, nuisance algae and CO2 Adds oxygen, pods and raises pH of your aquarium water Can't overflow onto your floor, because it is always under water No electrical parts go in the water, only air Can go on aquarium or sump wall if 5/8" (16mm) thick or less