--- product_id: 532406096 title: "MS300 Marine Grade Pond Sealant, Black, 300ml" brand: "mypond" price: "€ 43.78" currency: EUR in_stock: true reviews_count: 13 category: "My Pond" url: https://www.desertcart.gr/products/532406096-ms300-marine-grade-pond-sealant-black-300ml store_origin: GR region: Greece --- # 4x stronger waterproof seal Bonds to 12+ surfaces Cures underwater in 24h MS300 Marine Grade Pond Sealant, Black, 300ml **Brand:** mypond **Price:** € 43.78 **Availability:** ✅ In Stock ## Summary > 💧 Seal it once, seal it right — the ultimate marine-grade fix for every leak! ## Quick Answers - **What is this?** MS300 Marine Grade Pond Sealant, Black, 300ml by mypond - **How much does it cost?** € 43.78 with free shipping - **Is it available?** Yes, in stock and ready to ship - **Where can I buy it?** [www.desertcart.gr](https://www.desertcart.gr/products/532406096-ms300-marine-grade-pond-sealant-black-300ml) ## Best For - mypond enthusiasts ## Why This Product - Trusted mypond brand quality - Free international shipping included - Worldwide delivery with tracking - 15-day hassle-free returns ## Key Features - • **Aquatic Life Safe 🐟:** Non-toxic once cured, ensuring your koi, turtles, and aquatic plants thrive in a healthy environment. - • **Unmatched Strength 💪:** 4x stronger than traditional silicone for rock-solid, leak-proof seals that last. - • **Rapid Underwater Cure ⏳:** Apply directly on wet or submerged surfaces and get full cure in just 24 hours—no draining needed. - • **Multi-Surface Mastery 🧰:** Seamlessly bonds to concrete, glass, metal, wood, plastic, and more for versatile DIY and pro projects. - • **Flexible & Weatherproof 🌦️:** Remains permanently flexible, resisting cracks and shrinkage even under extreme outdoor conditions. ## Overview MS300 Marine Sealant is a premium 300ml hybrid MS polymer adhesive that delivers 4x stronger waterproof sealing than standard silicone. It cures underwater in 24 hours, bonds to over a dozen materials including concrete, glass, and metal, and is completely safe for aquatic life once dry. Perfect for ponds, aquariums, windows, and outdoor repairs, it offers durable, flexible protection that withstands weather and movement—ideal for professionals and DIY enthusiasts aiming for flawless, long-lasting results. ## Description Product Description MS300 Marine Sealant Choose What Works for You! MS300 Sealant Black MS300 Sealant Clear STYX Clear Sealant Vacuum Suction Lifter Double Union Ball Valve 3 Stage HMA Unit Wood Timber Screws Can this sealant be applied to a pond or aquarium while it’s filled with water, or must the surface be dry first? It can be applied directly to wet or submerged areas. This underwater sealant fully cures in 24 hours and becomes a pond sealant fish safe once dry, making it ideal for aquariums, koi ponds, fountains, and other aquatic environments. Can this sealant be applied to a pond or aquarium while it’s filled with water, or must the surface be dry first? It can be applied directly to wet or submerged areas. This underwater sealant fully cures in 24 hours and becomes a pond sealant fish safe once dry, making it ideal for aquariums, koi ponds, fountains, and other aquatic environments. Will the sealant bond effectively to a wide range of surfaces like wood, metal, plastic, stone, and glass? Yes, this hybrid polymer sealant offers strong, flexible adhesion to glass, stone, plastic, and more. It also performs well as a glass sealant, ensuring waterproof protection and long-term durability on a variety of indoor and outdoor surfaces. Will the sealant bond effectively to a wide range of surfaces like wood, metal, plastic, stone, and glass? Yes, this hybrid polymer sealant offers strong, flexible adhesion to glass, stone, plastic, and more. It also performs well as a glass sealant, ensuring waterproof protection and long-term durability on a variety of indoor and outdoor surfaces. Once the sealant is fully cured, is it safe for all aquatic life, including koi fish, turtles, and amphibians? Once cured, it’s completely non-toxic. It works as a koi pond sealer and pond sealer safe for fish, reptiles, and amphibians. Ideal for tanks, ponds, or habitats where the safety of aquatic animals and plants is critical and long-lasting. Once the sealant is fully cured, is it safe for all aquatic life, including koi fish, turtles, and amphibians? Once cured, it’s completely non-toxic. It works as a koi pond sealer and pond sealer safe for fish, reptiles, and amphibians. Ideal for tanks, ponds, or habitats where the safety of aquatic animals and plants is critical and long-lasting. Is this suitable for sealing bathrooms, kitchen sinks, or windows where strong waterproofing is essential? Absolutely. It works as a window sealer and waterproof silicone for high-moisture areas like showers, tiles, sinks, and windows. It delivers long-lasting protection, prevents mold buildup, and provides a clean, nearly invisible finish. Is this suitable for sealing bathrooms, kitchen sinks, or windows where strong waterproofing is essential? Absolutely. It works as a window sealer and waterproof silicone for high-moisture areas like showers, tiles, sinks, and windows. It delivers long-lasting protection, prevents mold buildup, and provides a clean, nearly invisible finish. Will this product stay flexible after curing, especially when exposed to outdoor temperatures and movement? Yes, it remains permanently flexible after curing. This adhesive sealant resists cracking or shrinking, even in changing temperatures. Ideal as a floor sealant and for roofs, walls, garden features, and high-movement outdoor joints. Will this product stay flexible after curing, especially when exposed to outdoor temperatures and movement? Yes, it remains permanently flexible after curing. This adhesive sealant resists cracking or shrinking, even in changing temperatures. Ideal as a floor sealant and for roofs, walls, garden features, and high-movement outdoor joints. Review: Sticks well - Good stuff done the job Review: Fixed half barrel nature pond leaks - My half barrel nature pond was leaking at the top. I used this to plug the leaks & it worked really well. I didn’t have to drain the pond first which saved a lot of work. Would definitely use again. ## Features - RELIABLE DIY POND REPAIR SOLUTION: MyPond heavy duty A+ grade hybrid adhesive or hybrid sealant make repairs and upgrades simple for DIY enthusiasts and professionals. This marine grade pond sealant helps you fix leaks and improve your pond or aquarium for long-lasting results. Our marine grade silicone sealant, waterproof hybrid polymer sealant works excellently as a pond leak sealer, fountain sealer, and even a koi pond sealer, ensuring durability for all your water features. - STRONGER THAN TRADITIONAL SILICONE: Our pond sealant fish safe is 4 times stronger than regular waterproof silicone sealant, providing superior sealing power for your pond and water features. Whether you need a pond sealer, pond leak sealer, or aquarium MS polymer sealant, our marine grade MS polymer adhesive sealant ensures fewer repairs and long-lasting protection. It also works well as a glass sealant, window sealant, pond window sealer, or even a gutter sealant for rain gutters. - FAST CURING UNDERWATER: This waterproof MS polymer glue cures underwater in just 24 hours, saving you time and hassle on your DIY pond projects. Ideal for use as a pond sealer, pond leak sealer, or underwater sealant, it provides quick, reliable results. Whether you're sealing a fish pond or repairing an aquarium, this aquarium silicone black marine silicone, pond sealer for leaks ensures your projects are completed efficiently, with lasting results. - VERSATILE AND FLEXIBLE BONDING: Our MS polymer adhesive bonds securely to materials like concrete, stone, wood, glass, metal, rubber, plastic, and fiberglass. This makes it a versatile choice for a wide range of projects, including as an aquarium sealant, aquarium caulk, window crack repair and marine sealant for all water-based applications. It works as a fish pond sealant, fountain sealer, and even for koi pond repairs. - FISH-SAFE FORMULA FOR AQUATIC LIFE: Ensure the safety of your aquatic life with our pond sealer safe for fish. This fish pond sealant is great for maintaining a healthy, natural environment in your pond. Whether you're using it as a pond leak sealer, marine grade MS polymer sealant, aquarium MS polymer sealant, or reptile safe sealant, our MyPond MS300 sealant, marine caulking keeps your water feature safe for fish, plants, and reptiles alike. ## Technical Specifications | Specification | Value | |---------------|-------| | ASIN | B0C2VBJ2BL | | Best Sellers Rank | 1,843 in Garden ( See Top 100 in Garden ) 27 in Pond Care & Water Treatment | | Brand | MyPond | | Compatible Material | Concrete, Stone, Wood, Glass, Metal, Rubber, Plastic, Fiberglass, Acrylic, Glass Reinforced Plastic, Porcelain, Vinyl, StoneConcrete, Stone, Wood, Glass, Metal, Rubber, Plastic, Fiberglass, Acrylic, Glass Reinforced Plastic, Porcelain, Vinyl, Stone | | Customer Reviews | 4.5 out of 5 stars 366 Reviews | | Item Form | Liquid | | Item form | Liquid | | Manufacturer | MyPond | | Manufacturer Part Number | Ms-300 | | Material | Silyl Polyether Polymer | | Number of Items | 1 | | Number of Packs | 1 | | Style | Compact | | Style Name | Compact | | Surface Recommendation | Window | | Unit Count | 300.0 millilitre | | Water Resistance Level | Waterproof | | Water resistance level | Waterproof | ## Product Details - **Brand:** MyPond - **Item form:** Liquid - **Style:** Compact - **Unit count:** 300.0 millilitre - **Water resistance level:** Waterproof ## Images ![MS300 Marine Grade Pond Sealant, Black, 300ml - Image 1](https://m.media-amazon.com/images/I/61vFY6Ju-xL.jpg) ![MS300 Marine Grade Pond Sealant, Black, 300ml - Image 2](https://m.media-amazon.com/images/I/71pFy3uKrfL.jpg) ![MS300 Marine Grade Pond Sealant, Black, 300ml - Image 3](https://m.media-amazon.com/images/I/71n77lvWQaL.jpg) ![MS300 Marine Grade Pond Sealant, Black, 300ml - Image 4](https://m.media-amazon.com/images/I/81EXuXEJY7L.jpg) ![MS300 Marine Grade Pond Sealant, Black, 300ml - Image 5](https://m.media-amazon.com/images/I/61mwfuR4C0L.jpg) ## Questions & Answers **Q: Can this sealant be applied to a pond or aquarium while it’s filled with water, or must the surface be dry first?** A: It can be applied directly to wet or submerged areas. This underwater sealant fully cures in 24 hours and becomes a pond sealant fish safe once dry, making it ideal for aquariums, koi ponds, fountains, and other aquatic environments. **Q: Will the sealant bond effectively to a wide range of surfaces like wood, metal, plastic, stone, and glass?** A: Yes, this hybrid polymer sealant offers strong, flexible adhesion to glass, stone, plastic, and more. It also performs well as a glass sealant, ensuring waterproof protection and long-term durability on a variety of indoor and outdoor surfaces. **Q: Once the sealant is fully cured, is it safe for all aquatic life, including koi fish, turtles, and amphibians?** A: Once cured, it’s completely non-toxic. It works as a koi pond sealer and pond sealer safe for fish, reptiles, and amphibians. Ideal for tanks, ponds, or habitats where the safety of aquatic animals and plants is critical and long-lasting. **Q: Is this suitable for sealing bathrooms, kitchen sinks, or windows where strong waterproofing is essential?** A: Absolutely. It works as a window sealer and waterproof silicone for high-moisture areas like showers, tiles, sinks, and windows. It delivers long-lasting protection, prevents mold buildup, and provides a clean, nearly invisible finish. **Q: Will this product stay flexible after curing, especially when exposed to outdoor temperatures and movement?** A: Yes, it remains permanently flexible after curing. This adhesive sealant resists cracking or shrinking, even in changing temperatures. Ideal as a floor sealant and for roofs, walls, garden features, and high-movement outdoor joints. ## Customer Reviews ### ⭐⭐⭐⭐⭐ Sticks well *by M***. on 3 July 2026* Good stuff done the job ### ⭐⭐⭐⭐⭐ Fixed half barrel nature pond leaks *by M***E on 16 July 2026* My half barrel nature pond was leaking at the top. I used this to plug the leaks & it worked really well. I didn’t have to drain the pond first which saved a lot of work. Would definitely use again. ### ⭐⭐⭐⭐⭐ Pond glass sealant *by D***L on 29 July 2026* Great product ## Frequently Bought Together - MyPond MS300 Marine Sealant, Window Sealer, Pond Sealer for Leaks Concrete Glass Metal, MS Polymer Adhesive 4x Stronger than Aquarium Silicone Caulking, Black Pond Liner Marine Adhesive Sealant, 300ml - Gorilla Waterproof Patch & Seal Tape Black 3m - Double Sided Butyl Tape Used for Membrane Jointing, Waterproofing, Pond Liner Repair (50MM X 1.5MM X 10M) --- ## 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.gr/products/532406096-ms300-marine-grade-pond-sealant-black-300ml](https://www.desertcart.gr/products/532406096-ms300-marine-grade-pond-sealant-black-300ml) --- *Product available on Desertcart Greece* *Store origin: GR* *Last updated: 2026-08-06*