BaoZqua Undergravel Filter System for 20–40 Gallon Fish Tank, Air-Driven Biofiltration Aquarium Filter Kit with 20 Modular Plates & 2 Adjustable Lift

BaoZqua Undergravel Filter System for 20–40 Gallon Fish Tank, Air-Driven Biofiltration Aquarium Filter Kit with 20 Modular Plates & 2 Adjustable Lift

Complete Filter Kit: Includes 20 interlocking filter plates, 2 adjustable lift tube set (with fitting), 2 check valve, 2 regulator, 2 extra air stone, 2 x 39" extra airline tubing, 1 airline tee connector, and all required connectors—everything to build your undergravel system. (Please note: air pump and tank are not included and must be prepared separately.) Efficient Undergravel Filtration: An external air pump (not included) supplies continuous airflow that drives water circulation, pulling water downward through the substrate and filter plates to trap debris and fines—delivering clear, clean water and steady flow in fish tanks. Biofiltration & Aeration: Beneficial nitrifying microbes colonize the gravel bed and plate surfaces to break down ammonia and nitrite. Air-driven flow oxygenates the water column, supporting active fish behavior and a stable biological cycle for a cleaner, balanced tank. Modular Plate Design: Includes 20 snap-fit undergravel plates (coverage up to 22.04" x 13.78"). Fine 0.06" mesh helps keep sand/gravel from fall-through; sturdy base helps resist bottom cracks and holds heavy substrate, improving water circulation and biofiltration in freshwater or saltwater tanks. Easy Installation: Tool-free setup—lay plates, add substrate, attach the lift tube, and connect to an air pump (not included). The lift tube is adjustable and DIY cut-to-fit; use the included check valve to help stop backflow, and for 20–40 gal aquariums we recommend a quiet 6–10W air pump for optimal flow. BaoZqua undergravel filter system is a modular, air-driven filtration solution designed for small to medium aquariums that want clearer water, better circulation, and a stable biological base under the substrate. By pairing the filter plates with an external air pump (sold separately), the system pulls water downward through the gravel bed and then lifts it back up through the riser tube. This under-bed circulation helps trap fine waste inside the gravel layer, supports microbial growth on the plates and substrate, and keeps water moving through the bottom of the tank instead of letting debris settle in dead spots. The system comes in three selectable sizes so hobbyists can match it to their tank: 6-plate kit with 1 lift tube – fits about 5–10 gallon aquariums 12-plate kit with 1 lift tube – fits about 10–20 gallon aquariums 20-plate kit with 2 lift tubes – fits about 20–40 gallon aquariums Each plate uses a snap-fit, build-any-layout design. Plates feature fine 0.06" gaps to keep sand/gravel from falling through, and the reinforced base is made to hold heavier substrates such as planted-tank gravel. Lift tubes are height-adjustable and can be trimmed to match the waterline of different tanks. This under gravel aquarium filter is ideal for setups that want air-driven biofiltration, optional pump-powered circulation, or even a canister-linked dual-filtration layout. Every kit includes the core parts you need to assemble the platform—filter plates, lift tube(s), airline tubing, check valve, flow regulator, and extra air stone—so installation stays plug-and-play. Just connect to your own air pump (6–10 W for 20–40 gal, higher wattage for bigger tanks) and the system will help improve clarity and flow over time. Air pump, submersible pump, and canister filter are not included, so please prepare your own equipment if you want to use those configurations.