--- product_id: 34808292 title: "Grech CBG-800 5W UV Sterilizer Hang-On Back Filter, 20-50 gallon/211 GPH, Black" brand: "grech" price: "£63.40" currency: GBP in_stock: true reviews_count: 8 category: "Grech" url: https://www.desertcart.co.uk/products/34808292-grech-cbg-800-5w-uv-sterilizer-hang-on-back-filter store_origin: GB region: United Kingdom --- # 211 GPH Flow Rate 9x5x7 in Dimensions 5W UV Sterilizer Grech CBG-800 5W UV Sterilizer Hang-On Back Filter, 20-50 gallon/211 GPH, Black **Brand:** grech **Price:** £63.40 **Availability:** ✅ In Stock ## Summary > 🌊 Dive into Clarity with the Ultimate Aquarium Filter! ## Quick Answers - **What is this?** Grech CBG-800 5W UV Sterilizer Hang-On Back Filter, 20-50 gallon/211 GPH, Black by grech - **How much does it cost?** £63.40 with free shipping - **Is it available?** Yes, in stock and ready to ship - **Where can I buy it?** [www.desertcart.co.uk](https://www.desertcart.co.uk/products/34808292-grech-cbg-800-5w-uv-sterilizer-hang-on-back-filter) ## Best For - grech enthusiasts ## Why This Product - Trusted grech brand quality - Free international shipping included - Worldwide delivery with tracking - 15-day hassle-free returns ## Key Features - • **Crystal Clear Waters:** Experience pristine aquarium clarity with advanced UV sterilization. - • **Efficient Filtration:** Dual biological and mechanical filtration for optimal water quality. - • **User-Friendly Design:** Easy setup with a simple push to start the impeller. - • **Versatile Compatibility:** Perfectly suited for 20-50 gallon tanks, making it a versatile choice. - • **Surface Skimmer Included:** Eliminate unsightly surface films for a cleaner aquarium look. ## Overview The GRECHCBG-800 5W UV Sterilizer Hang-On Back Filter is designed for aquarium enthusiasts, providing a powerful 211 GPH flow rate and a 5W UV sterilizer to keep your tank crystal clear. Suitable for 20 to 50-gallon tanks, it features dual filtration and a surface skimmer, ensuring optimal water quality and aesthetic appeal. ## Description The Grech CBG-Series Hang-On Back UV Filter offers a versatile and convenient filtration solution for freshwater and saltwater aquariums. Designed in a user-friendly “Hang-On Back” style, it provides easy installation, quiet operation, and adjustable water flow to suit your tank’s needs. The CBG-Series combines mechanical and biological filtration with included activated carbon and bio media for efficient water clarification. Its integrated 5W UV clarifier can be turned on or off to support clear, bright water. The adjustable surface skimmer helps reduce surface buildup, keeping your aquarium looking clean and well-maintained. Ideal for home aquariums, tropical fish tanks, and planted setups. Review: Amazing HOB filter at this price! - The UV feature is amazing when setting up a new tank or if you get an algae bloom. I set up a 10 gallon tank for some guppies and platies and within a week the water clouded up due to an algae bloom (typical for a new tank). I turned on the UV light and within days it was crystal clear. Once it cleared up, I turned off the UV lamp and the water has stayed perfect. I also like the filter design. You don't need to purchase expensive same-brand cassettes/filters or anything. You can use your own media and build up the filter however you like. I'm using ceramic bio rings, crushed coral in a mesh bag, and the foam that came with it. The water is crystal clear and all water parameters are exactly where I want them. Lastly, but not the least important thing I love about this filter is that it re-primes itself after a power outage! I have tried several other small HOBs that couldn't and they burned themselves out due to lack of water at the impeller. As long as this filter stays in the tank and water levels are where they should be, it has restarted EVERY SINGLE TIME we've had a power outage. One outage was 4 hours long and this was humming along when I got home. Other notables: - it's quiet - easy to set up - easy to clean - flow is adjustable - it has a surface skimmer that is adjustable and works great Review: Very Impressed So Far - I was a bit skeptical when I ordered this but I have a problem 40g tank and needed either more or better filtration. As much as I'd like to, I can't put a canister on this setup unless I want to tear it apart and move it. not gonna happen anytime soon. I liked that this hob has both the protein skimmer and uv sterilizer. And that the input flow for both the skimmer and the intake are adjustable individually. Seems like all stock media with any filter is low quality, no surprise. I did keep the sponge, loaded both trays with the media of my choice, fitted it all together, dropped it in and fired it up. ... Its been on the tank about two weeks now and I'm impressed so far. Its not the quietest, but quieter than others. The uv light is working great. Ive been running the light off and on for about 12 hours at a time over the last 2 weeks, and the bright green algae spots have almost all disappeared. The water is the clearest its ever been in this tank. The protein skimmer can be a bit noisey, but once you find the right flow adjustment it doesn't seem to be a problem. But, the true test is yet to come. I do still have the previous hob running , its the one that didn't seem to be doing its job well. I figured a month with both running to get the bacteria in the new filter, then I will remove the original hob and see how this one does by itself. I'll try to remember to come back and update my review, too. ## Features - Adjustable 211gph Filter Flow Rate with Surface Skimmer to eliminate undesired surface films - Features a 5W UV Sterilizer. Helps eliminate algae and bacteria, keeping aquarium water crystal clear - Suitable Aquarium Tank Size: 20 to 50 Gallons - Dimension: 9 x 5 x 7in (229 x 127.5 x 179mm) - Biological and mechanical filtration. Box includes active carbon and bio media - Note: Give the impeller “flywheel” a little push to start as magnet sometime stuck to certain position when sitting in the box for a long period of time. ## Technical Specifications | Specification | Value | |---------------|-------| | Customer Reviews | 4.0 out of 5 stars 803 Reviews | ## Images ![Grech CBG-800 5W UV Sterilizer Hang-On Back Filter, 20-50 gallon/211 GPH, Black - Image 1](https://m.media-amazon.com/images/I/612Xq+O6KoL.jpg) ![Grech CBG-800 5W UV Sterilizer Hang-On Back Filter, 20-50 gallon/211 GPH, Black - Image 2](https://m.media-amazon.com/images/I/81nTIl1EDoL.jpg) ![Grech CBG-800 5W UV Sterilizer Hang-On Back Filter, 20-50 gallon/211 GPH, Black - Image 3](https://m.media-amazon.com/images/I/81x-bsAaT0L.jpg) ![Grech CBG-800 5W UV Sterilizer Hang-On Back Filter, 20-50 gallon/211 GPH, Black - Image 4](https://m.media-amazon.com/images/I/81aa6yEJpmL.jpg) ![Grech CBG-800 5W UV Sterilizer Hang-On Back Filter, 20-50 gallon/211 GPH, Black - Image 5](https://m.media-amazon.com/images/I/816288RUhNL.jpg) ## Available Options This product comes in different **Size** options. ## Questions & Answers **Q: Will 2 of these would work for a 75 gallon tank. The reviews so far look good on this item.** A: I use one in a 55 gal. tank, so two should be plenty for a 75 gal. **Q: Can this replace a protein skimmer as well? right now i have a hang on filter & hang on skimmer, as well as a uv. i'm looking to combine them** A: It does have a surface skimmer built in the only issue can be fish fry. You can always put a sponge over it, but most of the time I see my fry stay away from it. Depends on the size of your tank. I would say this filter is good up to 40 gallons by itself. **Q: The impeller is working, so why is my filter only shooting out a small amout of water every 30 seconds?** A: Take the filter out and pull open the power block, pull the impeller, make sure there's no gunk in there and make sure the impeller is inserted all the way. Had this happen with one of mine - this fixed it. **Q: Having issues with it fitting a 60 gallon it won’t fit over the lip. I don’t want to force it to break the plastic. Has anyone else had this issue?** A: I had the same problem. I ended up needing to use a small hacksaw and cut a groove in the plastic border of my tank. Hope you do better with your filter than I've done with mine. FWIW, I don't think this filter will handle a 60 gallon tank. I have a rough time with mine just handling a less than 40 gallon tank. ## Customer Reviews ### ⭐⭐⭐⭐⭐ Amazing HOB filter at this price! *by M***H on October 27, 2024* The UV feature is amazing when setting up a new tank or if you get an algae bloom. I set up a 10 gallon tank for some guppies and platies and within a week the water clouded up due to an algae bloom (typical for a new tank). I turned on the UV light and within days it was crystal clear. Once it cleared up, I turned off the UV lamp and the water has stayed perfect. I also like the filter design. You don't need to purchase expensive same-brand cassettes/filters or anything. You can use your own media and build up the filter however you like. I'm using ceramic bio rings, crushed coral in a mesh bag, and the foam that came with it. The water is crystal clear and all water parameters are exactly where I want them. Lastly, but not the least important thing I love about this filter is that it re-primes itself after a power outage! I have tried several other small HOBs that couldn't and they burned themselves out due to lack of water at the impeller. As long as this filter stays in the tank and water levels are where they should be, it has restarted EVERY SINGLE TIME we've had a power outage. One outage was 4 hours long and this was humming along when I got home. Other notables: - it's quiet - easy to set up - easy to clean - flow is adjustable - it has a surface skimmer that is adjustable and works great ### ⭐⭐⭐⭐⭐ Very Impressed So Far *by J***7 on April 15, 2019* I was a bit skeptical when I ordered this but I have a problem 40g tank and needed either more or better filtration. As much as I'd like to, I can't put a canister on this setup unless I want to tear it apart and move it. not gonna happen anytime soon. I liked that this hob has both the protein skimmer and uv sterilizer. And that the input flow for both the skimmer and the intake are adjustable individually. Seems like all stock media with any filter is low quality, no surprise. I did keep the sponge, loaded both trays with the media of my choice, fitted it all together, dropped it in and fired it up. ... Its been on the tank about two weeks now and I'm impressed so far. Its not the quietest, but quieter than others. The uv light is working great. Ive been running the light off and on for about 12 hours at a time over the last 2 weeks, and the bright green algae spots have almost all disappeared. The water is the clearest its ever been in this tank. The protein skimmer can be a bit noisey, but once you find the right flow adjustment it doesn't seem to be a problem. But, the true test is yet to come. I do still have the previous hob running , its the one that didn't seem to be doing its job well. I figured a month with both running to get the bacteria in the new filter, then I will remove the original hob and see how this one does by itself. I'll try to remember to come back and update my review, too. ### ⭐⭐⭐⭐ The skimmers can be a big problem, but there's a fix *by B***S on March 23, 2026* I like this pump and have two of them in my 26 gal tank (overkill, yes). What I've learned, though, is that the UV may/will help if your water is cloudy. My water has always been clear, but I've instead had algae growing on surfaces in the tank. A couple of bristle nose plecos has fixed that much. But to me there is a significant issue with the skimmers. Everything worked fine for several months until the skimmers on both pumps simultaneously began oscillating up and down, causing the pump to cavitate and unprime itself. It was very, very noisy and I'm sure the pumps were running at reduced efficiency. The fix, finally, was to pull out the skimmers and stuff in cork stoppers from some bottles of port (wine corks are surely fine if they fit). Instantly, the pumps were super quiet and functioning at full efficiency. I'm not sure that the skimmers ever did much in my tank except to suck down a couple of my smallest fish. That won't happen anymore, either. ## Frequently Bought Together - Grech CBG-800 5W UV Sterilizer Hang-On Back Filter, 20-50 gallon/211 GPH, Black - AquaClear 50 Foam Filter Inserts, Aquarium Filter Replacement Media, 3 Count (Pack of 1), A1394 - Aqua Clear AquaClear Activated Carbon Filter Inserts, 3 Pack – Replacement Chemical Filter Media for 50 Gallon Tank --- ## 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.co.uk/products/34808292-grech-cbg-800-5w-uv-sterilizer-hang-on-back-filter](https://www.desertcart.co.uk/products/34808292-grech-cbg-800-5w-uv-sterilizer-hang-on-back-filter) --- *Product available on Desertcart United Kingdom* *Store origin: GB* *Last updated: 2026-05-26*