---
product_id: 107473470
title: "Hydrothol Aquatic Herbicide 20# Bag- Endothol 11%"
brand: "united phosphorus inc"
price: "€ 325.76"
currency: EUR
in_stock: true
reviews_count: 8
category: "United Phosphorus Inc"
url: https://www.desertcart.pt/products/107473470-hydrothol-aquatic-herbicide-20-bag-endothol-11
store_origin: PT
region: Portugal
---

# Fast-acting aquatic weed control Covers 1000 sq ft water surface 11.2% Endothall concentration Hydrothol Aquatic Herbicide 20# Bag- Endothol 11%

**Brand:** united phosphorus inc
**Price:** € 325.76
**Availability:** ✅ In Stock

## Summary

> 🌿 Clear waters, clear mind — conquer pond weeds like a pro!

## Quick Answers

- **What is this?** Hydrothol Aquatic Herbicide 20# Bag- Endothol 11% by united phosphorus inc
- **How much does it cost?** € 325.76 with free shipping
- **Is it available?** Yes, in stock and ready to ship
- **Where can I buy it?** [www.desertcart.pt](https://www.desertcart.pt/products/107473470-hydrothol-aquatic-herbicide-20-bag-endothol-11)

## Best For

- united phosphorus inc enthusiasts

## Why This Product

- Trusted united phosphorus inc brand quality
- Free international shipping included
- Worldwide delivery with tracking
- 15-day hassle-free returns

## Key Features

- • **Rapid Results:** Visible weed and algae clearance within days at optimal water temps
- • **Broad Coverage:** Effectively treats up to 1000 sq ft of lakes, ponds, and drainage canals
- • **Easy Application:** Granular form spreads effortlessly for hassle-free treatment
- • **Eco-Conscious Formula:** Safe for aquatic life when used as directed, preserving your ecosystem
- • **Precision Aquatic Control:** Targets stubborn pondweed and algae without harming fish

## Overview

Hydrothol Aquatic Herbicide delivers 11.2% Endothall in a 20-pound granular bag, expertly formulated to control aquatic weeds and algae across 1000 square feet of water surfaces such as lakes, ponds, and drainage canals. Trusted for its fast action and fish-safe profile, it’s the go-to solution for maintaining pristine aquatic environments with minimal effort.

## Description

Hydrothol

Review: Works well on curly leaf pondweed - Seems to work on curly leaf pondweed -- especially when treated early enough (about 50F water temp).
Review: Handling Invasive Aquatic Species - The product works as intended. It is extremely important to follow instructions and receive authorization for use from State Authorities before using.

## Features

- Hydrothol 191 Granular: Hydrothol Granular uses 11.2% concentrated Mono (N, N-dimethylalkylamine) Salt of Endothall, and continues to be a highly effective herbicide/algaecide solution for a variety of aquatic nuisances. Be sure to apply this product when weeds and algae are actively growing. Susceptibility of algae may vary due to subspecies, strains or environmental conditions. There is also a liquid option but this is sold to commercial applicators only. Check permitting requirements in your area prior to applying.
- EFFECTIVE HERBICIDE AND ALGAECIDE: Hydrothol Aquatic Herbicide and Algaecide has been successfully used for over 30 years. Today Hydrothol is used primarily as an algaecide. Hydrothol is the only registered broad spectrum organic aquatic algaecide available today. Hydrothol can be used in combination, in rotation or as an alternative to copper for control of algae.
- ENVIRONMENTALLY SOUND: Hydrothol quickly dissipates in the environment. When properly used, Hydrothol provides excellent algae and weed control, but does not adversely impact the fishery or the aquatic environment. Hydrothol does not bio accumulate in either fish or the hydro soil, and has a short half-life of less than seven days.
- VERSATILE: Due to the fast activity of Hydrothol , it can be effectively used in slow moving water, such as drainage and irrigation canals. In addition, spot or marginal treatments are highly effective against noxious weeds and algae in lakes and ponds. Hydrothol is effective in muddy or murky water because it does not bind to the suspended sediment or organic matter.
- HYDROTHOL: Hyrdothol provides control where you need it, in the application area, not away from the target area. For this reason, Hydrothol is a valuable tool in improving access to the water for recreational activities such as swimming, fishing and water skiing.
- APPLICATION: Hydrothol must be properly used to avoid toxicity to fish. Only marginal or sectional treatments are recommended and should be only be made by qualified commercial applicators. Applications should be made outward from the shoreline or in strips to prevent trapping fish in the treated zone. Refer to label for proper application rates. Kill lakeweeds.
- EFFECTS OF ALGAE: Algae can be detrimental to water quality. In fact, it may cause illness to swimmers and other water users. Poor water quality as a result of certain strains of algae may even prevent water-contact recreational uses including swimming, water skiing and use of personal water craft. Algae blooms are the leading cause of fish kills in the U.S., compromising fishery management programs.

## Technical Specifications

| Specification | Value |
|---------------|-------|
| ASIN | B00QXNR7AE |
| Active Ingredients | Herbicide |
| Best Sellers Rank | #11,599 in Patio, Lawn & Garden ( See Top 100 in Patio, Lawn & Garden ) #46 in Water Garden & Pond Treatment |
| Brand | United Phosphorus Inc |
| Brand Name | United Phosphorus Inc |
| Coverage | 1000 square feet |
| Customer Reviews | 4.2 out of 5 stars 468 Reviews |
| Global Trade Identification Number | 39270356680801 |
| Item Form | Granules |
| Item Weight | 20 Pounds |
| Liquid Volume | 9463.52 Milliliters |
| Manufacturer | United Phosphorus Inc |
| Part Number | 6020396 |
| Unit Count | 320.0 Ounce |

## Product Details

- **Brand:** United Phosphorus Inc
- **Item Weight:** 20 Pounds
- **Liquid Volume:** 9463.52 Milliliters
- **Item Form:** Granules
- **Active Ingredients:** Herbicide

## Images

![Hydrothol Aquatic Herbicide 20# Bag- Endothol 11% - Image 1](https://m.media-amazon.com/images/I/71qHAqnsybL.jpg)

## Questions & Answers

**Q: Does this kill water shield, cat tails, willows and algae ?**
A: Hi...yes it does kill water shield, cat tails and other water vegatation as long as you get it spread in close proximity to the base of those plants...not sure about the willows, suspect not because they are above the water.  I prefer to keep a little patch of ws and ct so I carefully spreading the granular product allowing me to do that.  For algea no...different type of animal...I used Cutrine Plus...spray on algea after it forms...works great other than I have to spray it 4-5 times during the year to keep it under control.  Looking for a different product that you toss in and it prevents the algea from starting.

**Q: Will this kill Hydrilla?**
A: I used this for leafy pond grass and it kills numerous other. It also takes care of algae.
My pond has never looked as clean as it does now.

**Q: Do you just throw it in on the algae? I'm asking because mine is broken up in sections I already applied another product and it helped a little but I**
A: That is what we did.  This stuff sinks and gets to the roots.. about a week Lily pads started to look burnt and drying up.

**Q: River application + I live o. A river in Maine, will this work on weeds under the water?**
A: Hydrotho Granular aquatic herbicide and algaecide for ponds provides rapid-acting contact control for submerged weeds and algae. Hydrothol even works where there is moving water such as a canal or bay area. Hydrothol can be used in combination, in rotation or as an alternative to copper for control of algae. Dosage rates vary depending on what type of algae or weed is being treated and the density of the infestation.

## Customer Reviews

### ⭐⭐⭐⭐⭐ Works well on curly leaf pondweed
*by J***R on December 26, 2025*

Seems to work on curly leaf pondweed -- especially when treated early enough (about 50F water temp).

### ⭐⭐⭐⭐⭐ Handling Invasive Aquatic Species
*by R***W on May 27, 2026*

The product works as intended. It is extremely important to follow instructions and receive authorization for use from State Authorities before using.

### ⭐⭐⭐⭐⭐ Pond Problem Solver
*by A***N on August 9, 2025*

Cleared out stubborn algae in just a few days. Easy to spread and works fast without harming the fish.

## Frequently Bought Together

- Hydrothol Aquatic Herbicide 20# Bag- Endothol 11%
- Airmax MuckAway Natural Beneficial Bacteria for Outdoor Ponds & Lakes, Muck, Sludge & Noxious Odor Solution, Easy to use Enzyme Tablets, Cleaner Beach & Shoreline, Fish, Pet & Wildlife Safe, 8 Scoops
- Cutrine-Plus Granulated Algaecide - 30 lbs. Professional-Grade Algae Killer for Lakes & Ponds, EPA Approved to Control All Types of Algae (Planktonic, Filamentous, and Chara)

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*Product available on Desertcart Portugal*
*Store origin: PT*
*Last updated: 2026-06-22*