--- product_id: 472415247 title: "Airmax Knockdown Defense 2-in-1 Liquid Pond Algae Control, Effective & Fast Acting Algaecide, Aquatic Weed Treatment for Clear Water in Ponds & Lakes, Liquid Formulation for Easy Use, 16 fl oz" brand: "airmax" price: "€ 200.65" currency: EUR in_stock: true reviews_count: 8 category: "Airmax" url: https://www.desertcart.at/products/472415247-airmax-knockdown-defense-2-in-1-liquid-pond-algae-control store_origin: AT region: Austria --- # Targets 7+ invasive aquatic species 16 fl oz liquid formula 3-5 days fast action Airmax Knockdown Defense 2-in-1 Liquid Pond Algae Control, Effective & Fast Acting Algaecide, Aquatic Weed Treatment for Clear Water in Ponds & Lakes, Liquid Formulation for Easy Use, 16 fl oz **Brand:** airmax **Price:** € 200.65 **Availability:** βœ… In Stock ## Summary > πŸ’¦ KnockDown Defense: Fast, fierce, and flawless pond perfection! ## Quick Answers - **What is this?** Airmax Knockdown Defense 2-in-1 Liquid Pond Algae Control, Effective & Fast Acting Algaecide, Aquatic Weed Treatment for Clear Water in Ponds & Lakes, Liquid Formulation for Easy Use, 16 fl oz by airmax - **How much does it cost?** € 200.65 with free shipping - **Is it available?** Yes, in stock and ready to ship - **Where can I buy it?** [www.desertcart.at](https://www.desertcart.at/products/472415247-airmax-knockdown-defense-2-in-1-liquid-pond-algae-control) ## Best For - airmax enthusiasts ## Why This Product - Trusted airmax brand quality - Free international shipping included - Worldwide delivery with tracking - 15-day hassle-free returns ## Key Features - β€’ **Rapid Restoration:** Clears ponds & lakes in just 3-5 days, so you never miss a moment of crystal-clear water. - β€’ **Versatile Water Use:** Safe for ponds, lakes, canals, and slow-moving water β€” perfect for professional-grade aquatic management. - β€’ **Long-Lasting Defense:** Innovative combo treatment keeps your aquatic environment pristine longer, reducing repeat applications. - β€’ **Broad-Spectrum Control:** Effectively eliminates floating algae, duckweed, hydrilla, and more β€” conquering 7+ invasive species. - β€’ **Precision Liquid Formula:** Easy-to-measure 16 fl oz liquid ensures hassle-free mixing and application with your tank sprayer. ## Overview KnockDown Defense is a powerful 16 fl oz liquid aquatic herbicide designed to rapidly eliminate a wide range of invasive weeds and algae in ponds, lakes, and slow-moving waters. Delivering visible results within 3-5 days, it combines fast action with long-lasting control, making it an essential solution for maintaining clear, healthy aquatic environments. ## Description desertcart.com : Airmax Knockdown Defense 2-in-1 Liquid Pond Algae Control, Effective & Fast Acting Algaecide, Aquatic Weed Treatment for Clear Water in Ponds & Lakes, Liquid Formulation for Easy Use, 16 fl oz : Patio, Lawn & Garden Review: Aquatic weed killer and algae - This is really good stuff, but definitely do not make it too strong. It will even kill grass around. The pond if made to strong a bit pricey though Review: Incredibly effective for duckweed. Killed all vegetation. - Absolutely blown away with how effective this product is. I used a single application as directed and it removed 100% of the duckweed in about 2 weeks. I planned a second treatment, but patience was all that was needed. Incredible product, wish I found it sooner. Also this pond is used for irrigation of the lawn and beds. I waited 5 days as per instructions before using for irrigation and had not issues with my lawn or plants. After pic shown first. ## Features - Powerful formula: KnockDown Defense eliminates a variety of invasive weeds and algae including: floating algae, watermeal, duckweed, watermilfoil, fanwort, hydrilla, and more. KnockDown Defense is effective in ponds, lakes, and slow moving or inactive water such as canals. - Fast results: Whether you’re dealing with floating algae or submerged aquatic plants, KnockDown works fast to eliminate algae and weeds to restore your pond or lake in 3-5 days. - Liquid formulation: KnockDown Defense is a liquid algae control and aquatic herbicide that is easy to measure, mix, and apply. For best results, apply aquatic weed control treatment with a surfactant and a tank sprayer. - Innovative solution: KnockDown Defense is a fast-acting and long-lasting combination treatment for both algae and pond weed control. Developed to be effective on even the toughest invasive lake weeds and algae. - For ponds & lakes: KnockDown Defense provides fast-acting, long-lasting pond weed control. Use 0.75-1.5 fluid ounces of KnockDown Defense for every 1/8 acre or roughly 5,500 sq/ft. Use as directed. ## Technical Specifications | Specification | Value | |---------------|-------| | ASIN | B0B3Y5Z1S8 | | ASIN | B0B3Y5Z1S8 | | Best Sellers Rank | #19,618 in Patio, Lawn & Garden ( See Top 100 in Patio, Lawn & Garden ) #56 in Water Garden & Pond Treatment | | Brand Name | Airmax | | Customer Reviews | 4.4 4.4 out of 5 stars (112) | | Date First Available | June 13, 2022 | | Item Form | Liquid | | Liquid Volume | 16 Fluid Ounces | | Manufacturer | Airmax, Inc. | | Manufacturer | Airmax, Inc. | | Manufacturer Part Number | 530268 | | Product Dimensions | 5 x 2 x 9 inches; 1.43 Pounds | | Target Species | Aquatic Plants | | UPC | 810089840295 | | Unit Count | 16.0 Fluid Ounces | ## Product Details - **Brand:** Airmax - **Item Form:** Liquid - **Liquid Volume:** 16 Fluid Ounces - **Manufacturer:** Airmax, Inc. - **UPC:** 810089840295 ## Images ![Airmax Knockdown Defense 2-in-1 Liquid Pond Algae Control, Effective & Fast Acting Algaecide, Aquatic Weed Treatment for Clear Water in Ponds & Lakes, Liquid Formulation for Easy Use, 16 fl oz - Image 1](https://m.media-amazon.com/images/I/51OUdezWiuL.jpg) ## Available Options This product comes in different **Color, Size** options. ## Customer Reviews ### ⭐⭐⭐⭐⭐ Aquatic weed killer and algae *by G***T on February 23, 2026* This is really good stuff, but definitely do not make it too strong. It will even kill grass around. The pond if made to strong a bit pricey though ### ⭐⭐⭐⭐⭐ Incredibly effective for duckweed. Killed all vegetation. *by A***R on July 20, 2025* Absolutely blown away with how effective this product is. I used a single application as directed and it removed 100% of the duckweed in about 2 weeks. I planned a second treatment, but patience was all that was needed. Incredible product, wish I found it sooner. Also this pond is used for irrigation of the lawn and beds. I waited 5 days as per instructions before using for irrigation and had not issues with my lawn or plants. After pic shown first. ### ⭐⭐⭐⭐ No caps *by W***M on August 12, 2024* Received today with no caps. --- ## 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.at/products/472415247-airmax-knockdown-defense-2-in-1-liquid-pond-algae-control](https://www.desertcart.at/products/472415247-airmax-knockdown-defense-2-in-1-liquid-pond-algae-control) --- *Product available on Desertcart Austria* *Store origin: AT* *Last updated: 2026-04-22*