--- product_id: 49040210 title: "Fluval Cycle Biological Enhancer, 250 ml ( Packaging may vary)" brand: "fluval" price: "Β£16.97" currency: GBP in_stock: true reviews_count: 13 category: "Fluval" url: https://www.desertcart.co.uk/products/49040210-fluval-cycle-biological-enhancer-250-ml-packaging-may-vary store_origin: GB region: United Kingdom --- # Rapid ammonia & nitrite neutralization Instant beneficial bacteria boost Sustained water quality maintenance Fluval Cycle Biological Enhancer, 250 ml ( Packaging may vary) **Brand:** fluval **Price:** Β£16.97 **Availability:** βœ… In Stock ## Summary > 🦠 Transform your tank into a thriving aquatic sanctuaryβ€”no waiting, just winning! ## Quick Answers - **What is this?** Fluval Cycle Biological Enhancer, 250 ml ( Packaging may vary) by fluval - **How much does it cost?** Β£16.97 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/49040210-fluval-cycle-biological-enhancer-250-ml-packaging-may-vary) ## Best For - fluval enthusiasts ## Why This Product - Trusted fluval brand quality - Free international shipping included - Worldwide delivery with tracking - 15-day hassle-free returns ## Key Features - β€’ **Fast-Track Toxicity Control:** Highly effective micro-organisms rapidly metabolize harmful ammonia and nitrite, preventing dangerous spikes. - β€’ **Trusted by Enthusiasts Worldwide:** Top-ranked aquarium water treatment with thousands of 5-star reviews backing its performance. - β€’ **Jumpstart Your Aquarium's Ecosystem:** Immediate inoculation with powerful beneficial bacteria ensures a safe, stable habitat from day one. - β€’ **Safe for Immediate Fish Introduction:** Enables adding fish right away by establishing essential biological flora quickly. - β€’ **Build a Resilient Biological Foundation:** Regular use excludes harmful bacteria, promoting long-term water health and quality. ## Overview Fluval Cycle Biological Enhancer is a premium liquid supplement that instantly introduces beneficial bacteria to new and established aquariums. It accelerates the nitrogen cycle by metabolizing toxic ammonia and nitrites, creating a safe environment for fish from day one. Regular application prevents harmful bacteria growth, ensuring long-term water quality and a healthy aquatic ecosystem. Ideal for freshwater tanks, it’s a must-have for proactive aquarium managers seeking hassle-free, vibrant fish habitats. ## Description Product Description Fluval Biological Enhancer is a responsive biological aquarium supplement that ensures that all aquariums are immediately inoculated with a powerful team of beneficial bacteria, providing a safe biological habitat for your fish. These highly effective micro-organisms will create a biological flora that quickly metabolises lethal ammonia and nitrite, and allow for the immediate introduction of fish. The Fluval Biological Enhancer is strongly recommended for new aquarium set-ups and regular application will help to exclude the establishment of undesirable bacteria in aquariums. Directions The product_description from the external source provides the following instructions: 1. Use Fluval Cycle Biological Enhancer for new aquariums to establish safe and essential conditions. 2. Apply the product regularly to competitively exclude undesirable bacteria in aquariums. 3. Add the product to aquarium water to eliminate toxic ammonia and nitrites, creating a biologically well-balanced aquarium for healthy fish to thrive. Box Contains Cycle Review: Does the job - As described Review: Maintain a healthy Aquarium - I use this product when setting up a new aquarium (as part of the nitrogen cycle to promote healthy ammonia eating bacteria growth, a 6 to 8 week process) and as part of my weekly water changes. I feel that this product works very well, as my fish are all happy and healthy and I have never experienced any bad water quality issues (ammonia spikes etc). I use this weekly to add to my 200ltr, 60ltr and 30ltr aquariums when I do a water change. I change 20% - 30% of the water volume and add an appropriate dose of this stuff, however it's not really possible to overdose so it does not really matter if you add a little bit extra. I usually do add a bit more than stated on the label. I keep it stored at room temperature and the 2ltr bottle usually lasts me about 6 weeks. There is always a seal covering the opening after the lid has been unscrewed, so you know it is brand new and has not been opened / tampered with. This is safe for my fresh water aquarium inhabitants, of which I have many varieties. Pros: - The larger 2ltr bottle is excellent value compared to the 250ml or 500ml bottles - Quick delivery / repeat orders available - Far cheaper than my local pet store Cons: - Nothing I can think of really I hope this review has been helpful to you. Happy Fish Keeping! ## Features - Fluval Biological Enhancer provides immediate inoculation with a powerful team of beneficial bacteria, creating a safe and stable biologial habitat for your fish from day one - Highly effective micro-organisms quickly metabolise harmful ammonia and nitrite, helping prevent toxic spikes and supporting a healthier enivornment - Recommended to aquarium set ups, as it helps to establish essential biological flora right from the beginning - Regular application of the Biological Enhancher helps to exclude the establishment of harmful or undesirable bacteria, promoting water health and quality long-term - Using the water treatment builds up a robust foundation against bacteria, therefore enabling a safe environment for immediate addition of fish to your tank ## Technical Specifications | Specification | Value | |---------------|-------| | ASIN | B00FPIZ8Y0 | | Best Sellers Rank | 660 in Pet Supplies ( See Top 100 in Pet Supplies ) 3 in Aquarium Water Treatments | | Brand | Fluval | | Brand Name | Fluval | | Country Of Origin | United Kingdom | | Customer Reviews | 4.6 out of 5 stars 6,792 Reviews | | Global Trade Identification Number | 00015561183499 | | Item Form | Liquid | | Item Type Name | Cycle Biological Aquarium water treatment | | Item Weight | 8.45 Ounces | | Item form | Liquid | | Item weight | 8.45 Ounces | | Liquid Volume | 8.4 Fluid Ounces | | Liquid volume | 8.4 Fluid Ounces | | Manufacturer | Rolf C Hagen UK Ltd | | Manufacturer Part Number | A8349 | | Model Number | A8349 | | Number of Items | 1 | | Pet Type | Amphibian, Fish, Reptile | | Target Species | Fish | | UPC | 015561183499 | | Unit Count | 1 count | | Unit count | 1 count | ## Product Details - **Brand:** Fluval - **Item form:** Liquid - **Item weight:** 8.45 Ounces - **Liquid volume:** 8.4 Fluid Ounces - **Unit count:** 1 count ## Images ![Fluval Cycle Biological Enhancer, 250 ml ( Packaging may vary) - Image 1](https://m.media-amazon.com/images/I/71CbLgtkAbL.jpg) ## Questions & Answers **Q: i have a 240l tank how much cycle do i use in my tank it is a new tank.** A: Tip the whole bottle in your filter **Q: Can this be used to boost some established bio media in a new tank?** A: Yes definately. Put it in the tank as instructions say. Then keep putting a min og 10 ml in until your happy. I used it for setting up new 200 ltr tank and it's the only stuff I used after that. **Q: Can I use this in salt water?** A: Having read the information on the back of the bottle it says that it is safe for use in fresh and salt water aquariums. **Q: I want to add new fish into my established tank. Can I add this into the tank, let the bag with new fish float for a while then release the fish?** A: No! What you must do is add this after following the instructions and leave for a few days for the bacteria to establish a proper environment for the fish before they are added. Try reading a book or 3 on setting up a fish tank. ## Customer Reviews ### ⭐⭐⭐⭐⭐ Does the job *by R***B on 17 August 2026* As described ### ⭐⭐⭐⭐⭐ Maintain a healthy Aquarium *by M***D on 3 April 2021* I use this product when setting up a new aquarium (as part of the nitrogen cycle to promote healthy ammonia eating bacteria growth, a 6 to 8 week process) and as part of my weekly water changes. I feel that this product works very well, as my fish are all happy and healthy and I have never experienced any bad water quality issues (ammonia spikes etc). I use this weekly to add to my 200ltr, 60ltr and 30ltr aquariums when I do a water change. I change 20% - 30% of the water volume and add an appropriate dose of this stuff, however it's not really possible to overdose so it does not really matter if you add a little bit extra. I usually do add a bit more than stated on the label. I keep it stored at room temperature and the 2ltr bottle usually lasts me about 6 weeks. There is always a seal covering the opening after the lid has been unscrewed, so you know it is brand new and has not been opened / tampered with. This is safe for my fresh water aquarium inhabitants, of which I have many varieties. Pros: - The larger 2ltr bottle is excellent value compared to the 250ml or 500ml bottles - Quick delivery / repeat orders available - Far cheaper than my local pet store Cons: - Nothing I can think of really I hope this review has been helpful to you. Happy Fish Keeping! ### ⭐⭐⭐⭐⭐ First Class *by A***R on 14 November 2024* I got a new aquarium so new substrate, new filter, (new everything, basically). I filled the tank and let it run for a few days then added the first dose of the recommended three day initial course of Fluval Cycle. On day two a test strip showed all levels of potential concern (ph, chlorine, carbonate, total hardness, nitrite and nitrate) were within acceptable parameters. Accordingly it looks like I could have introduced fish before I had even introduced the second measure. Instead I waited until after the third dose, introduced some neon tetras and two catfish and they are as happy as any fish I have seen in established tanks. I'm confident further measures of Fluval Cycle weekly, at water changes and when introducing new fish can only be beneficial. ## Frequently Bought Together - Fluval Cycle Biological Enhancer, Aquarium Water Treatment, 8.4 Oz., A8349 - Fluval Waste Control Biological Cleaner, Aquarium Water Treatment, 8.4 Oz., A8355 - Fluval Clarify Bio for Aquarium Water Treatment, 4-Ounce --- ## Why Shop on Desertcart? - πŸ›’ **Trusted by 1.3+ Million Shoppers** β€” Serving international shoppers since 2016 - 🌍 **Shop Globally** β€” Access 737+ million products across 21 categories - πŸ’° **No Hidden Fees** β€” All customs, duties, and taxes included in the price - πŸ”„ **15-Day Free Returns** β€” Hassle-free returns (30 days for PRO members) - πŸ”’ **Secure Payments** β€” Trusted payment options with buyer protection - ⭐ **TrustPilot Rated 4.5/5** β€” Based on 8,000+ happy customer reviews **Shop now:** [https://www.desertcart.co.uk/products/49040210-fluval-cycle-biological-enhancer-250-ml-packaging-may-vary](https://www.desertcart.co.uk/products/49040210-fluval-cycle-biological-enhancer-250-ml-packaging-may-vary) --- *Product available on Desertcart United Kingdom* *Store origin: GB* *Last updated: 2026-10-04*