--- product_id: 374373518 title: "Fluval Cycle Biological Enhancer, 250 ml (Packaging may vary)" brand: "fluval" price: "968 kr" currency: NOK in_stock: true reviews_count: 5 category: "Fluval" url: https://www.desertcart.no/products/374373518-fluval-cycle-biological-enhancer-250-ml-packaging-may-vary store_origin: NO region: Norway --- # Safe for plants, fish & humans Eliminates toxic ammonia & nitrite Instant beneficial bacteria boost Fluval Cycle Biological Enhancer, 250 ml (Packaging may vary) **Brand:** fluval **Price:** 968 kr **Availability:** βœ… In Stock ## Summary > 🦠 Transform your tank into a thriving aquatic paradise! ## Quick Answers - **What is this?** Fluval Cycle Biological Enhancer, 250 ml (Packaging may vary) by fluval - **How much does it cost?** 968 kr with free shipping - **Is it available?** Yes, in stock and ready to ship - **Where can I buy it?** [www.desertcart.no](https://www.desertcart.no/products/374373518-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€’ **Eco-Friendly & Safe:** Formulated to be completely harmless to plants, animals, and humans alike. - β€’ **Effortless Tank Maintenance:** Ideal for new setups and ongoing water quality support without complicated chemicals. - β€’ **Toxic-Free Water, Happy Fish:** Effectively eliminates harmful ammonia and nitrite to protect your aquatic pets. - β€’ **Trusted by Thousands of Aquarists:** Highly rated with 4.7 stars and a proven track record for reliable aquarium health. - β€’ **Jumpstart Your Aquarium's Nitrogen Cycle:** Powerful bacterial blend activates immediately for a healthy aquatic ecosystem. ## Overview Fluval Cycle Biological Enhancer is a 250 ml liquid supplement that instantly introduces beneficial bacteria to new or established aquariums, accelerating the nitrogen cycle. It safely eliminates toxic ammonia and nitrite, ensuring a healthy environment for fish and plants without harmful chemicals. Trusted by thousands, it’s essential for anyone serious about maintaining a vibrant, balanced aquarium. ## Description Product Description Fluval Cycle biological aquarium supplement for new tank startups and regular maintenance 250ml. Set Contains: Cycle Review: Cool! - Vielen Dank! Top! Gern wieder ! Review: JUST STARTED USING, HAVE NOW BOUGHT AGAIN - Just upgraded my rating to 5 stars, after tentative 4 star rating, now that the product has proven itself! HIGHLY RECOMMENDED . . . tank is crystal, crystal clear after use while adding many new fish over just a couple of days. I immediately ordered it again. This is my new "best buy" for this type of product. **Initial Review** I've used Jungle StartZyme for years, then gave Tetra SafeStartPlus a try. They have worked very well but I was shopping for a better price/larger size for "start-up" bacteria. FluvalHagen is a respected, established name and the product description read better than others I was considering so I bought this. Have only used it once but could see the difference in the tank overnight. I noticed while reading through many of the reviews on these bacterial "quick start" products that many people had negative things to say to the effect that they are useless or don't work . . . They DO Work! The short version is the tank must "cycle" to make an aquarium work properly for the fish to survive and be healthy. No amount of filtration can substitute for the natural cycle of beneficial bacteria that "eat" the fish waste & uneaten food in an aquarium. Bacteria are needed to do that. These "bacteria in a bottle" make that happen much faster, instantly for the most part. I also noticed some users were adding this before they have fish in the tank . . . bacteria and fish work together. There's no point in adding this type of product to an empty tank, the bacteria need the fish waste so they have something to eat! The fish need the bacteria so they don't get sick/die in their own waste before the cycle is balanced. A couple of **hints** for those new to fish keeping: overfeeding is the biggest problem with fish. Do Not feed more than the fish clean up within 5 minutes! It's a lot less than you think. It's fun to feed the fish but every single bit that isn't eaten immediately pollutes the tank and that's what kills the fish. Better a few small feedings than one big one. Do Not put too many fish in your tank, the "rule" is an inch of fish per gallon of water and the bigger the fish the bigger the mess! Don't add all the fish you want at once. Set the tank up, add this product, then add your first few fish. That can be done the first day, you don't have to look at an empty tank but feed very sparingly. That lets you figure out how much to feed while the filter starts to populate with bacteria. If the water stays clear, doesn't smell and the fish are doing good, then you can add a few more fish. Use this "liquid bacteria" per the instructions until you have successfully established the aquarium, then do your regular water changes as there needs to be "new water" in and "old water out, about a 3rd of the volume every month. There's no substitute for regular water changes, light feeding and live bacteria in the tank regardless of the type of fish or aquarium . . . be it a jar with a Betta or a fancy set up full of expensive exotic fish. ## Features - Powerful team of beneficial bacteria immediately inoculates aquarium water - Creates a safe biological habitat for your fish - Eliminates ammonia and nitrite - Will not harm plants; animals or humans - Size: 8.4 oz. ## Technical Specifications | Specification | Value | |---------------|-------| | ASIN | B00FPIZ8Y0 | | Best Sellers Rank | #66,342 in Pet Supplies ( See Top 100 in Pet Supplies ) #538 in Fish Medication & Health Supplies | | Brand | Fluval | | Brand Name | Fluval | | Customer Reviews | 4.7 out of 5 stars 3,626 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 | Hagen | | 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 - **Manufacturer:** Hagen ## Images ![Fluval Cycle Biological Enhancer, 250 ml (Packaging may vary) - Image 1](https://m.media-amazon.com/images/I/71CbLgtkAbL.jpg) ![Fluval Cycle Biological Enhancer, 250 ml (Packaging may vary) - Image 2](https://m.media-amazon.com/images/I/91rfNNwDfYL.jpg) ![Fluval Cycle Biological Enhancer, 250 ml (Packaging may vary) - Image 3](https://m.media-amazon.com/images/I/91-Evy96NLL.jpg) ![Fluval Cycle Biological Enhancer, 250 ml (Packaging may vary) - Image 4](https://m.media-amazon.com/images/I/91lZke+rb-L.jpg) ![Fluval Cycle Biological Enhancer, 250 ml (Packaging may vary) - Image 5](https://m.media-amazon.com/images/I/81+iaCLv3AL.jpg) ## Questions & Answers **Q: How much do I need for setting up a new 75g freshwater tank?** A: After tank is set up, keep everything running except for lights and if you are running a saltwater tank keep the protein skimmer off. Pour in half of 16.9 oz. bottle upon set up, On the 8th day ,pour the rest in. In my experience on day 14 your tank is cycled, however testing tank water , 1 time I had to wait 16 days. It is recommended to dose the tank when new arrivals are added, I did this for 1week then stopped, I have used this item for 15 years when the original was sold under the CYCLE name which came in 8oz. and 16 oz. Works every time. **Q: What size bottle is recommended for a 6 gallon tank?** A: The 8.4 oz seems like a better deal overall compare to the 1oz and 4 oz. its a little cheaper. However, you would need this every time you do a water change. Some people don't add more when then do a water change, but when you take out water from your tank, your taking out some of the bacteria, thats why its necessary to replace the bacteria. This is by far one of my favorite nitrifying bacteria. This is good to cycle a tank. Plus this bacteria is something you cannot overdose. So for a six gallon tank you can add three to 4 full caps to get a good amount of bacteria in there to start the cycle. Then you can add your first fish. After you add your first fish wait for a few weeks before you add more fish. The first initial fish will help feed the bacteria you put in. This way over a few weeks it will create the ecosystem you want. To be honest Allie, some people add two much fish the first time they get an aquarium and its a big mistake. Eventually they may have a lot of fish loss due to they tank not being a ecosystem. You want to make sure you create the ecosystem first before you add a lot of fishes. Thats why for the size of your tank one fish is ok with the addition of the bacteria will help create the ecosystem. After a few weeks you can add more. Also if you are doing tropical or saltwater fish make sure you have a heater. If your doing goldfish your not required to have a heater. Acclimate your fishes well too. If you have any more questions feel free to contact me. **Q: What size do I need for a 40 gallon breeder tank?** A: The directions state 25 ml per 10 gallons on day 1 (100 ml) and then 10 ml per 10 gallons on day 2 and 3 (40 ml per day) so a total of 180 ml for your 40 gallon breader. I do a sustainment treatment every week of 5 ml per 10 gallons (another 20 ml). I think this is a great way to get and keep a large colony of beneficial bacteria. Good luck with the new tank! **Q: If I put this in a new tank how quickly will it cycle the tank? Will the bacteria stay in the tank or die off after a bit? Is it cycled permanently?** A: I would recommend API Stress Zyne Plus. My fish kept dying for the first few weeks. It took almost 8 weeks to for the tank to cycle. So get 2 or 3 fist to start and nothing fancy. Keep testing for Amonia levels. Once the tank cycles, it should be at 0. Then you can get fish you want to keep. ## Customer Reviews ### ⭐⭐⭐⭐⭐ Cool! *by M***L on 24 September 2025* Vielen Dank! Top! Gern wieder ! ### ⭐⭐⭐⭐⭐ JUST STARTED USING, HAVE NOW BOUGHT AGAIN *by M***Y on 7 October 2019* Just upgraded my rating to 5 stars, after tentative 4 star rating, now that the product has proven itself! HIGHLY RECOMMENDED . . . tank is crystal, crystal clear after use while adding many new fish over just a couple of days. I immediately ordered it again. This is my new "best buy" for this type of product. **Initial Review** I've used Jungle StartZyme for years, then gave Tetra SafeStartPlus a try. They have worked very well but I was shopping for a better price/larger size for "start-up" bacteria. FluvalHagen is a respected, established name and the product description read better than others I was considering so I bought this. Have only used it once but could see the difference in the tank overnight. I noticed while reading through many of the reviews on these bacterial "quick start" products that many people had negative things to say to the effect that they are useless or don't work . . . They DO Work! The short version is the tank must "cycle" to make an aquarium work properly for the fish to survive and be healthy. No amount of filtration can substitute for the natural cycle of beneficial bacteria that "eat" the fish waste & uneaten food in an aquarium. Bacteria are needed to do that. These "bacteria in a bottle" make that happen much faster, instantly for the most part. I also noticed some users were adding this before they have fish in the tank . . . bacteria and fish work together. There's no point in adding this type of product to an empty tank, the bacteria need the fish waste so they have something to eat! The fish need the bacteria so they don't get sick/die in their own waste before the cycle is balanced. A couple of **hints** for those new to fish keeping: overfeeding is the biggest problem with fish. Do Not feed more than the fish clean up within 5 minutes! It's a lot less than you think. It's fun to feed the fish but every single bit that isn't eaten immediately pollutes the tank and that's what kills the fish. Better a few small feedings than one big one. Do Not put too many fish in your tank, the "rule" is an inch of fish per gallon of water and the bigger the fish the bigger the mess! Don't add all the fish you want at once. Set the tank up, add this product, then add your first few fish. That can be done the first day, you don't have to look at an empty tank but feed very sparingly. That lets you figure out how much to feed while the filter starts to populate with bacteria. If the water stays clear, doesn't smell and the fish are doing good, then you can add a few more fish. Use this "liquid bacteria" per the instructions until you have successfully established the aquarium, then do your regular water changes as there needs to be "new water" in and "old water out, about a 3rd of the volume every month. There's no substitute for regular water changes, light feeding and live bacteria in the tank regardless of the type of fish or aquarium . . . be it a jar with a Betta or a fancy set up full of expensive exotic fish. ### ⭐⭐⭐⭐⭐ Good price πŸ‘ *by W***R on 30 April 2026* Seems fine and good price πŸ‘Œ ## 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.no/products/374373518-fluval-cycle-biological-enhancer-250-ml-packaging-may-vary](https://www.desertcart.no/products/374373518-fluval-cycle-biological-enhancer-250-ml-packaging-may-vary) --- *Product available on Desertcart Norway* *Store origin: NO* *Last updated: 2026-09-25*