Reddit reviews Aquarium Technology, Inc. Filter Max III Foam Sponge Prefilter for Aquariums up to 40 Gallons

Extend filter media and replacement cartridge life while protecting small fish; simply connect to your impeller tube or powerhead to keep larger debris out of a sand filter, UV sterilizer, or protein skimmer.Trusted by casual hobbyists and pros alike - whether part of an internal or external power filtration system, the Filter Max is a great introductory point to sponge filters.Whisper-quiet and easy to clean - simply rinse and squeeze in used tank water (not tap water!) to maintain nitrogen-fixing bacteria in freshwater or saltwater.Soft foam filters across a wide surface area, creating bubbles to reduce protein buildup and increase oxygen. Ideal for low-current breeding, betta, discus, and turtle tanks.Fast-cycle a new tank by transferring a filter sponge from old to new. For even more pristine water try our Hydro-Sponge Pro line.