--- product_id: 4156361 title: "Flourish Potassium 500ml" brand: "seachem" price: "£19.92" currency: GBP in_stock: true reviews_count: 13 category: "Seachem" url: https://www.desertcart.co.uk/products/4156361-flourish-potassium-500ml store_origin: GB region: Great Britain --- # No phosphate or nitrate - pure plant nutrition 50,000 mg/L potassium concentration Precise dosing: 5 mL per 125 L raises K by 2 mg/L Flourish Potassium 500ml **Brand:** seachem **Price:** £19.92 **Availability:** ✅ In Stock ## Summary > 🌿 Elevate your aquarium’s green game — don’t let your plants settle for less! ## Quick Answers - **What is this?** Flourish Potassium 500ml by seachem - **How much does it cost?** £19.92 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/4156361-flourish-potassium-500ml) ## Best For - seachem enthusiasts ## Why This Product - Trusted seachem brand quality - Free international shipping included - Worldwide delivery with tracking - 15-day hassle-free returns ## Key Features - • **Algae-Resistant Formula:** No phosphates or nitrates means plants get nutrients first, limiting algae growth. - • **Tailored Dosing Control:** Easily adjust potassium levels with precise 5 mL capful dosing for any tank size. - • **Trusted by Aquascaping Pros:** Highly rated and proven effective for thriving planted aquariums with minimal algae. - • **Boost Plant Growth Naturally:** Delivers essential potassium to fuel lush, vigorous aquatic plants. - • **Synergizes with Flourish Line:** Optimized to work seamlessly with Seachem’s full plant care range for maximum vitality. ## Overview Seachem Flourish Potassium is a high-concentration potassium supplement (50,000 mg/L) designed specifically for freshwater planted aquariums. It contains no phosphates or nitrates, ensuring plants receive pure potassium without encouraging algae growth. The product features precise dosing instructions (5 mL per 125 L raises potassium by 2 mg/L) to prevent nutrient deficiencies and promote robust plant health. Ideal for use alongside the full Flourish line, it supports rapid, healthy plant growth and is trusted by aquarists worldwide. ## Description Sachem Flourish Potassium contains 50,000 mg/L of potassium suitable for the natural freshwater aquarium. Potassium is one of several elements that are vitally important to maintaining a vigorous level of growth in a planted aquarium. Potassium can become depleted in a rapidly growing system or when the source water has a low mineral content. In these cases potassium could become the limiting factor to growth. Use Flourish Potassium to prevent potassium depletion and maintain the highest level of growth. Flourish Potassium is an integral component of Sachem's plant products and is recommended for use with the entire Flourish line as well as our Fluorite gravel. Contains no phosphate or nitrate. Review: Great, little goes a long way, effective - I use a little less than half recommended bottle dosage every day of all seachem ferts (rotate days between trace and flourish complete). Also use online co2 calculator and use just below dose of co2 tank from 5 am to 5pm. Then I air stone at night. Slightly underused recommended fish food once or twice a day. I take no days off. 2/3rd water change and vacuum every 10 days. Perfect numbers and very slow minimal acceptable algae growth on walls to be hardly visibly noticeable. I created my own HOB power filter and pre-filter using a number of materials from desertcart sources. I only clean the sponges and not the physical media, squeeze them out in the throw out water that comes out during water change. Aquarium maintenance 101 from a newbie. Use as little substrate as possible to keep plants alive to more easily avoid snails. Clean literally everything before putting into aquarium, better for it to die before going in aquarium than to introduce snails. Scrape the walls of algae at each waterchange. If you get snails, take literally everything out but fish and inverts, and soak it in a low ratio bleach plus water bath for like 20 minutes, this is the only way to kill all pest snails literally. Drain the water to just enough for the fish and inverts to swim and live, then scrub the entire aquarium with a scraper and take out literally anything you can see. Scrape again 3 times. Wipe it all down and make sure all there is you can see is the fish and inverts and clear water. Then wipe again. Add plenty of cycling bacteria from multiple sources you can find on desertcart including seachem. Refill the aquarium with the bleach soaked plants decorations subtrate and filter medias. MAKE SURE YOU SOAK IN PLENTY OF DECHLORINATOR AND WATER FOR 20 MINUTES first. None of your plants should die off completely but they will lose and have killed a good amount of their leaves and roots but they should survive and regrow if you fert and change new water and quick cycle with added bacteria I truly hope this helps. My first year with a fully stocked nano tank has been a lot of time reading and experimenting. The pest snail battle was epic but I've been free for 6 months completely. I win. Oh and didn't lose a fish or invert and plants are beyond original growth. This is with having done zero quarantining or adapting at any point. I also cycled from day one, no precycling. Use a 24 hour light with cycling phases and full K spectrum for plants. It is way easier and effective and worth the minor price increase over standard lights. And it is fun Also add Indian leaves and a UV filter Filter floss = crystal clear water. Chemical filtration is entirely unnecessary Have had no issues and made zero adjustments in six months everything has been clear and clean, green growth strong, living things have thrived. Electric heater w built in temperature control at 82 degrees for tropical fish and plants Review: Very powerful product for all planted aquariums - Seachem products are very helpful and essential to planted fish tanks for a variety of reasons. If you are just beginning to venture into a live planted aquarium, these are great products to dose. With that being said, you do have to use caution to not over do it. If you are researching this product, let me tell you why and how they work to help you make up your mind: 1. Using the proper doses of seachem products together help your plants grow firm, tall, and gain the beautiful glow they need. 2. Natural algae block!!! A common problem in planted aquariums is algae. Proper dosage of these products provide your plants with nutrients that are designed to be readily absorbed by your plants before algae can get it. Plants and algae compete in the aquarium for nutrients and proper use of seachem products will give your plants a jump start to suck up the nutrients before algae will get to it and grow. 3. Plants are a great natural filter for your aquarium and if you have fish that breed, the rapid growth will allow your fish great coverage and hiding areas to either lay eggs or have their babies. The list goes on and on about why these products do work well, but you have to remember to get everything together for a good planted aquarium to work. Seachem is wonderful enough to provide dosing regimens on their website. I successfully used it as a guide and tweaked it to what my plants needed. ## Features - Potassium supplement - For planted aquariums - Contains no phosphate or nitrate ## Technical Specifications | Specification | Value | |---------------|-------| | ASIN | B0002APILO | | ASIN | B0002APILO | | Age Range Description | All Life Stages | | Best Sellers Rank | #9,025 in Pet Supplies ( See Top 100 in Pet Supplies ) #72 in Aquarium Water Treatments | | Brand Name | Seachem | | Color | white | | Customer Reviews | 4.7 4.7 out of 5 stars (2,950) | | Date First Available | October 2, 2001 | | Date First Available | October 2, 2001 | | Department | Unisex-Adult | | Department | Unisex-Adult | | Directions | Use 1 capful (5 mL) for every 125 L (30 US gallons). This dose raises potassium by 2 mg/L. Repeat 2–3 times per week or as needed in response to signs of potassium deficiency in older leaves which include: chlorosis (yellowing), necrosis (death/browning), pinholes in leaves, and weak stems and roots. | | Included Components | Seachem Flourish Potassium 500ml | | Is Discontinued By Manufacturer | No | | Item Dimensions LxWxH | 7.6 x 1.5 x 1.5 inches | | Item Package Dimensions L x W x H | 8.23 x 2.68 x 2.52 inches | | Item Weight | 265 Grams | | Item model number | 463 | | Item model number | 463 | | Manufacturer | Seachem Laboratories, Inc. | | Manufacturer | Seachem Laboratories, Inc. | | Material | Plastic | | Model Name | Seachem Flourish Potassium 500ml | | Number of Items | 1 | | Product Dimensions | 7.6 x 1.5 x 1.5 inches; 9.35 ounces | | Size | 500 mL / 16.9 fl. oz. | | Specific Uses for Product | Active | | Target Audience Keyword | fish | | Warranty Description | Warranty | ## Product Details - **Brand:** Seachem - **Item Form:** Liquid - **Item Weight:** 265 Grams - **Liquid Volume:** 500 Milliliters - **Manufacturer:** Seachem Laboratories, Inc. ## Images ![Flourish Potassium 500ml - Image 1](https://m.media-amazon.com/images/I/51tnZl9nI-L.jpg) ## Available Options This product comes in different **Size** options. ## Customer Reviews ### ⭐⭐⭐⭐⭐ Great, little goes a long way, effective *by P***O on July 20, 2016* I use a little less than half recommended bottle dosage every day of all seachem ferts (rotate days between trace and flourish complete). Also use online co2 calculator and use just below dose of co2 tank from 5 am to 5pm. Then I air stone at night. Slightly underused recommended fish food once or twice a day. I take no days off. 2/3rd water change and vacuum every 10 days. Perfect numbers and very slow minimal acceptable algae growth on walls to be hardly visibly noticeable. I created my own HOB power filter and pre-filter using a number of materials from amazon sources. I only clean the sponges and not the physical media, squeeze them out in the throw out water that comes out during water change. Aquarium maintenance 101 from a newbie. Use as little substrate as possible to keep plants alive to more easily avoid snails. Clean literally everything before putting into aquarium, better for it to die before going in aquarium than to introduce snails. Scrape the walls of algae at each waterchange. If you get snails, take literally everything out but fish and inverts, and soak it in a low ratio bleach plus water bath for like 20 minutes, this is the only way to kill all pest snails literally. Drain the water to just enough for the fish and inverts to swim and live, then scrub the entire aquarium with a scraper and take out literally anything you can see. Scrape again 3 times. Wipe it all down and make sure all there is you can see is the fish and inverts and clear water. Then wipe again. Add plenty of cycling bacteria from multiple sources you can find on amazon including seachem. Refill the aquarium with the bleach soaked plants decorations subtrate and filter medias. MAKE SURE YOU SOAK IN PLENTY OF DECHLORINATOR AND WATER FOR 20 MINUTES first. None of your plants should die off completely but they will lose and have killed a good amount of their leaves and roots but they should survive and regrow if you fert and change new water and quick cycle with added bacteria I truly hope this helps. My first year with a fully stocked nano tank has been a lot of time reading and experimenting. The pest snail battle was epic but I've been free for 6 months completely. I win. Oh and didn't lose a fish or invert and plants are beyond original growth. This is with having done zero quarantining or adapting at any point. I also cycled from day one, no precycling. Use a 24 hour light with cycling phases and full K spectrum for plants. It is way easier and effective and worth the minor price increase over standard lights. And it is fun Also add Indian leaves and a UV filter Filter floss = crystal clear water. Chemical filtration is entirely unnecessary Have had no issues and made zero adjustments in six months everything has been clear and clean, green growth strong, living things have thrived. Electric heater w built in temperature control at 82 degrees for tropical fish and plants ### ⭐⭐⭐⭐⭐ Very powerful product for all planted aquariums *by J***E on August 6, 2015* Seachem products are very helpful and essential to planted fish tanks for a variety of reasons. If you are just beginning to venture into a live planted aquarium, these are great products to dose. With that being said, you do have to use caution to not over do it. If you are researching this product, let me tell you why and how they work to help you make up your mind: 1. Using the proper doses of seachem products together help your plants grow firm, tall, and gain the beautiful glow they need. 2. Natural algae block!!! A common problem in planted aquariums is algae. Proper dosage of these products provide your plants with nutrients that are designed to be readily absorbed by your plants before algae can get it. Plants and algae compete in the aquarium for nutrients and proper use of seachem products will give your plants a jump start to suck up the nutrients before algae will get to it and grow. 3. Plants are a great natural filter for your aquarium and if you have fish that breed, the rapid growth will allow your fish great coverage and hiding areas to either lay eggs or have their babies. The list goes on and on about why these products do work well, but you have to remember to get everything together for a good planted aquarium to work. Seachem is wonderful enough to provide dosing regimens on their website. I successfully used it as a guide and tweaked it to what my plants needed. ### ⭐⭐⭐⭐⭐ Flourish potassium *by K***V on February 11, 2026* Works well for holes in live aquarium fresh water plants very satisfied ## Frequently Bought Together - Seachem Flourish Potassium 500ml - Seachem Flourish Freshwater Plant Supplement 500 ml - Seachem Flourish Iron 500ml --- ## 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/4156361-flourish-potassium-500ml](https://www.desertcart.co.uk/products/4156361-flourish-potassium-500ml) --- *Product available on Desertcart Great Britain* *Store origin: GB* *Last updated: 2026-04-23*