--- product_id: 276327349 title: "Undergravel Aquarium Filter for 40-55 Gallon Tanks – Four 11.25” x 11.25” Plates – Under Gravel System for Clear, Clean Water – Safe for Freshwater and Saltwater Tanks" brand: "penn-plax" price: "€ 66.30" currency: EUR in_stock: true url: https://www.desertcart.hr/products/276327349-undergravel-aquarium-filter-for-40-55-gallon-tanks-four-11 store_origin: HR region: Croatia --- # Air-driven filtration system Dual filtration + aeration combo 4 large 11.25” x 11.25” filter plates Undergravel Aquarium Filter for 40-55 Gallon Tanks – Four 11.25” x 11.25” Plates – Under Gravel System for Clear, Clean Water – Safe for Freshwater and Saltwater Tanks **Brand:** penn-plax **Price:** € 66.30 **Availability:** ✅ In Stock ## Summary > 💧 Elevate your aquarium game with clean water and effortless style! ## Quick Answers - **What is this?** Undergravel Aquarium Filter for 40-55 Gallon Tanks – Four 11.25” x 11.25” Plates – Under Gravel System for Clear, Clean Water – Safe for Freshwater and Saltwater Tanks by penn-plax - **How much does it cost?** € 66.30 with free shipping - **Is it available?** Yes, in stock and ready to ship - **Where can I buy it?** [www.desertcart.hr](https://www.desertcart.hr/products/276327349-undergravel-aquarium-filter-for-40-55-gallon-tanks-four-11) ## Best For - penn-plax enthusiasts ## Why This Product - Trusted penn-plax brand quality - Free international shipping included - Worldwide delivery with tracking - 15-day hassle-free returns ## Key Features - • **Effortless Clarity:** Air pump powered for crystal-clear water with minimal moving parts—less hassle, more sparkle. - • **Quad-Plate Coverage:** Four expansive 11.25” x 11.25” plates ensure thorough filtration across your 40-55 gallon tank. - • **Aerate While You Filter:** Integrated aeration boosts oxygen levels, keeping your fish vibrant and thriving. - • **Complete Setup Included:** All essential components included—just add your air pump and watch your tank transform. - • **Triple-Action Filtration:** Biological, chemical, and physical filtration work in harmony for pristine aquatic health. ## Overview The Penn-Plax Undergravel Aquarium Filter is an air-driven filtration system designed for 40-55 gallon tanks, featuring four large 11.25” x 11.25” plates that provide biological, chemical, and physical filtration. It simultaneously aerates your tank, promoting a healthy aquatic environment with minimal maintenance and a sleek, unobtrusive design. ## Description Full description not available ## Features - NOTHING LIKE OLD SCHOOL: The Clear-Free Premium Under Gravel Filter is air driven and utilizes an Air Pump (not included) to cycle crystal clear water throughout your aquarium, while keeping a crisp and neat look inside. This means there’s less “moving parts,” making for simplistic and easy maintenance. This filter is suitable for most 40 – 55 gallon aquariums. - BIOLOGICAL, CHEMICAL, AND PHYSICAL FILTRATION: As air is pushed through the Air Stones and rises through the Lift Tubes, water is gently suctioned through gravel and the filter plates, allowing both air and water to pass through the Filt-a-Carb Activated Carbon Cartridges. When water continues to be drawn through, anaerobic bacteria collects and colonizes within the gravel and filter plates. - ALSO AERATES YOUR TANK: Since the Clear-Free Premium Under Gravel Filter is air driven through the use of Air Stones and an Air Pump (not included), it also aerates your tank. In essence, your aquarium is being filtered and aerated at the same time, though the same system. It’s a filter and bubbler in 1. - ITEMS INCLUDED: The Clear-Free Premium Under Gravel Filter includes 4 Filter Plates, 4 Adjustable Lift Tubes, 4 Straight Airline Tubes, 9 Filter Plate Connecters, and 4 Replaceable Filt-a-Carb Activated Carbon Media Cartridges. - MEASUREMENTS: Each Filter Plate Separately = 11.25” (W) x 11.25” (D) / Filter Plates Together = 45” (W) x 11.25” (D) / Each Lift Tube at Filter Plate Base = 13.25” – 16.5” ## Technical Specifications | Specification | Value | |---------------|-------| | Product Dimensions | 29.21 x 6.35 x 29.21 cm; 916.26 g | | Item model number | CFU55 | | Pet Life Stage | All Life Stages | | Allergen Information | Allergen-Free | | Color | Blue | | Size | 40 - 55 Gallons | | Number of Items | 1 | | Quantity | 1 | | Specific Uses | Indoor | | batteries required | No | | Batteries Included | No | | Item Weight | 916 g | ## Images ![Undergravel Aquarium Filter for 40-55 Gallon Tanks – Four 11.25” x 11.25” Plates – Under Gravel System for Clear, Clean Water – Safe for Freshwater and Saltwater Tanks - Image 1](https://m.media-amazon.com/images/I/819cRGofPsL.jpg) ## Available Options This product comes in different **Color, Size** options. ## Questions & Answers **Q: Hello! i have a 55 gallon tank. how does this filter work? does it come with everything i need? and if there is a video on it please send it. thanks** A: Thank you for your question. This filter has a plastic filter plate which lies under the gravel of the tank. This plate allows water to flow freely under the gravel. Water is drawn through the gravel and cleaned removing bateria and debris. In order for this air filter to work properly you will need an air pump as well as airline tubing. We like the Air Pod Pump B003DHYB52 and B0002563MW for air tubing. We don't have a video at this time but will have one soon. **Q: Can i configure this to fit a container that is 12.5" x 12.5"? Can experts recommend something better if not?** A: The 40/55 comes with four plates. Each plate has two tube attachments. One plate would fill a 12.5". Even if it were a little big you could score it (its plastic) and make it fit. **Q: Is it 11.5' square as in the decription or 13" as in the picture?** A: If you're getting it for a 55 gal aquarium the best I can tell you without tearing mine up out of my tank is that its perfect for the 55g , I've got them in my 10g , 39g bow front , 55g , and one in my 60g acrylic. **Q: What size should i get gor a 36 gallon tank** A: I have a 55 gallon tank and I used all the supplies flooring pieces, I think using this you may only require 3 of the flooring pieces possibly two if it’s a taller tank and not a show tank ## Frequently Bought Together - Penn-Plax Undergravel Aquarium Filter for 40-55 Gallon Tanks – Four 11.25” x 11.25” Plates – Under Gravel System for Clear, Clean Water – Safe for Freshwater and Saltwater Tanks (CFU55) - AQUANEAT Aquarium Air Pump 300GPH, for up to 200 Gallon Fish Tank, Powerful Hydroponic Aerator Pump with Tubing, Air Stones, Valves - Penn-Plax Standard Airline Tubing for Aquariums – Clear and Flexible – Resists Kinking – Safe for Freshwater and Saltwater Fish Tanks – 25 Feet --- ## Why Shop on Desertcart? - 🛒 **Trusted by 1.3+ Million Shoppers** — Serving international shoppers since 2016 - 🌍 **Shop Globally** — Access 737+ million products across 21 categories - 💰 **No Hidden Fees** — All customs, duties, and taxes included in the price - 🔄 **15-Day Free Returns** — Hassle-free returns (30 days for PRO members) - 🔒 **Secure Payments** — Trusted payment options with buyer protection - ⭐ **TrustPilot Rated 4.5/5** — Based on 8,000+ happy customer reviews **Shop now:** [https://www.desertcart.hr/products/276327349-undergravel-aquarium-filter-for-40-55-gallon-tanks-four-11](https://www.desertcart.hr/products/276327349-undergravel-aquarium-filter-for-40-55-gallon-tanks-four-11) --- *Product available on Desertcart Croatia* *Store origin: HR* *Last updated: 2026-07-14*