Hydrothol Granular Aquatic Algaecide & Herbicide 20 lb Bag
Hydrothol Granular Aquatic Algaecide & Herbicide 20 lb Bag
$11686
Clear bottom algae and reclaim weed-choked shoreline water with Hydrothol Granular Aquatic Algaecide and Herbicide, a granular endothall treatment for ponds, lakes, and canals. This EPA-registered formula controls both algae and submerged weeds, gives algae control in a few days, and lets you place treatment right where growth is active. Choose the 20 lb unit for smaller sectional work or the 40 lb unit for broader treatment zones.
- Fast-acting control; algae response can appear within days
- Dual-purpose treatment; manages algae and submerged weeds together
- Targeted placement; granules drop into problem areas
- Two size options; easier to match treatment scale
- Use-ready guidance; minimal water-use restrictions by label
- Trusted chemistry; EPA-registered aquatic formulation
Choose the size that fits your water depth, target growth, and treatment area.
Always follow label directions.
Recommended companion treatment program
NT-MAX Lake & Pond Clarifier + Sludge & Muck Digester Rapidly restore crystal clear conditions in lakes, ponds, and lagoons using NT-MAX, a high-performance biological clarifier powered by….
After using Hydrothol Granular Aquatic Algaecide and Herbicide, wait about 14 days before applying NT-MAX Lake & Pond Clarifier + Sludge & Muck Digester.
Bundle savings may be available below when eligible.
Frequently bought together
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Product Description
Fast, Targeted Control for Algae and Submerged Weeds
Hydrothol Granular is a practical choice when you need one granular treatment that can address both nuisance algae and submerged weeds in ponds, lakes, irrigation canals, and drainage canals. Its endothall-based contact action suits spot, sectional, shoreline, and dock-area treatments, while the 20 lb and 40 lb units make it easier to size the purchase to smaller jobs or broader treatment programs.
Key Features & Benefits
| Feature | Benefit |
|---|---|
| Granular endothall formula | Lets you place treatment directly where algae and weeds are active. |
| Controls weeds and algae | Useful when one water body has mixed nuisance growth. |
| Quick algae response | Supports faster visible cleanup when timing matters. |
| 20 lb and 40 lb units | Helps match purchase size to smaller sections or larger treatment zones. |
| EPA-registered aquatic label | Gives buyers a label-backed rate structure for planning. |
Directions & Dosing Snapshot
| Use Case | Label Rate | Application Notes |
|---|---|---|
| Light to moderate planktonic and filamentous algae | 0.05-0.3 ppm (3-16 lbs. per acre-foot) | Repeat when algae reappear and reach treatment levels. |
| Branched algae or difficult algae species | 0.3-3.0 ppm (16-162 lbs. per acre-foot) | Rates above 0.3 ppm are suggested only for commercial applicators as marginal or sectional treatments. |
| Submerged aquatic plants, general | 0.5-5.0 ppm (27-270 lbs. per acre-foot) | Use for plant control is suggested as marginal or sectional treatment due to fish-toxicity potential. |
| Hydrilla | 1-5 ppm (54-270 lbs. per acre-foot) | Rate selection depends on treatment goal and site conditions. |
| Milfoil, coontail, horned pondweed, or naiad | 1.5-2.5 ppm (81-135 lbs. per acre-foot) | Helpful for spot and sectional control in ponds and lakes. |
| Curlyleaf pondweed | 0.75-1.5 ppm (41-81 lbs. per acre-foot) | Lower labeled range than many other submerged weeds. |
| Ponds and small lakes with little to no outflow, average depth 4 ft | 15 lbs. per acre-foot at 0.25 ppm for planktonic and filamentous algae; 30 lbs. per acre-foot at 0.5 ppm for branched algae and aquatic plants | Apply to the perimeter or multiple perimeter points; early spring and at least 24 hours of contact time are preferred. |
Always follow the full label for complete directions, restrictions, and site-specific requirements.
Comparison Table
| Hydrothol Granular | Chelated copper granules | Granular submerged-weed herbicide | Biological pond-treatment program | |
|---|---|---|---|---|
| Primary role | Algae and submerged weeds | Algae-focused | Submerged weeds first | Organic-load management |
| Mechanism | Endothall contact granule | Copper contact algaecide | Varies by chemistry | Microbial maintenance approach |
| Application style | Direct granular broadcast | Direct granular broadcast | Direct granular broadcast | Repeated maintenance dosing |
| Water-use context | Minimal restrictions for swimming, fishing, and irrigation; label still governs potable-water and site limits | Varies by label | Varies by label | Varies by product |
| Best fit | Bottom algae, chara, and mixed submerged growth | Algae-only cleanup programs | Weed-only control programs | Long-term balance and sludge reduction |
Why Choose Granular Endothall?
- Dual-purpose control: One granular treatment can address algae and many submerged weeds in the same site.
- Cleaner placement: Granules are easy to target around docks, shorelines, coves, and spot-treatment zones.
- Better planning: The label gives ppm, acre-foot, and 1,000-square-foot depth-based rate structure for more confident sizing.
This product is distributed by NewTechBio as an authorized reseller. Specifications, treatment rates, and performance claims are sourced from the official EPA-approved manufacturer label and published documentation. NewTechBio does not independently verify manufacturer claims. Always read and follow the label.
Last updated for listing accuracy: 04/15/2026
What is Hydrothol Granular best used for?
Will it work if I have both bottom algae and submerged weeds in the same area?
How do I choose between the 20 lb and 40 lb units?
How do the application rates work in plain English?
How fast should I expect results?
What does Hydrothol Granular target?
Are there important restrictions I should know before buying?
Can I treat the whole pond at one time?
Will I still need beneficial microbes after treatment?
Products related to this item
Product Details
SKU: NTBIO3744336
UPC: 724235263626
Category: Algaecides, Herbicides
Brand: UPL
Weight: 20 lbs
Dimensions: 24 x 12 x 13 in
Important Information
SDS: View Safety Data Sheet (PDF)
LABEL (Directions & Rates): View Product Label (PDF)
Comments/Other: Review the Product Label and SDS for directions, rates, and safety information.
Certifications / Registrations: EPA registered
Origin: Locally Manufactured, Made in the USA
Feature: Granular formulation for targeted application, Ideal for spot treatments and shoreline management
Product Form: Granular
Product Details
Fast, Targeted Control for Algae and Submerged Weeds
Hydrothol Granular is a practical choice when you need one granular treatment that can address both nuisance algae and submerged weeds in ponds, lakes, irrigation canals, and drainage canals. Its endothall-based contact action suits spot, sectional, shoreline, and dock-area treatments, while the 20 lb and 40 lb units make it easier to size the purchase to smaller jobs or broader treatment programs.
Key Features & Benefits
| Feature | Benefit |
|---|---|
| Granular endothall formula | Lets you place treatment directly where algae and weeds are active. |
| Controls weeds and algae | Useful when one water body has mixed nuisance growth. |
| Quick algae response | Supports faster visible cleanup when timing matters. |
| 20 lb and 40 lb units | Helps match purchase size to smaller sections or larger treatment zones. |
| EPA-registered aquatic label | Gives buyers a label-backed rate structure for planning. |
Directions & Dosing Snapshot
| Use Case | Label Rate | Application Notes |
|---|---|---|
| Light to moderate planktonic and filamentous algae | 0.05-0.3 ppm (3-16 lbs. per acre-foot) | Repeat when algae reappear and reach treatment levels. |
| Branched algae or difficult algae species | 0.3-3.0 ppm (16-162 lbs. per acre-foot) | Rates above 0.3 ppm are suggested only for commercial applicators as marginal or sectional treatments. |
| Submerged aquatic plants, general | 0.5-5.0 ppm (27-270 lbs. per acre-foot) | Use for plant control is suggested as marginal or sectional treatment due to fish-toxicity potential. |
| Hydrilla | 1-5 ppm (54-270 lbs. per acre-foot) | Rate selection depends on treatment goal and site conditions. |
| Milfoil, coontail, horned pondweed, or naiad | 1.5-2.5 ppm (81-135 lbs. per acre-foot) | Helpful for spot and sectional control in ponds and lakes. |
| Curlyleaf pondweed | 0.75-1.5 ppm (41-81 lbs. per acre-foot) | Lower labeled range than many other submerged weeds. |
| Ponds and small lakes with little to no outflow, average depth 4 ft | 15 lbs. per acre-foot at 0.25 ppm for planktonic and filamentous algae; 30 lbs. per acre-foot at 0.5 ppm for branched algae and aquatic plants | Apply to the perimeter or multiple perimeter points; early spring and at least 24 hours of contact time are preferred. |
Always follow the full label for complete directions, restrictions, and site-specific requirements.
Comparison Table
| Hydrothol Granular | Chelated copper granules | Granular submerged-weed herbicide | Biological pond-treatment program | |
|---|---|---|---|---|
| Primary role | Algae and submerged weeds | Algae-focused | Submerged weeds first | Organic-load management |
| Mechanism | Endothall contact granule | Copper contact algaecide | Varies by chemistry | Microbial maintenance approach |
| Application style | Direct granular broadcast | Direct granular broadcast | Direct granular broadcast | Repeated maintenance dosing |
| Water-use context | Minimal restrictions for swimming, fishing, and irrigation; label still governs potable-water and site limits | Varies by label | Varies by label | Varies by product |
| Best fit | Bottom algae, chara, and mixed submerged growth | Algae-only cleanup programs | Weed-only control programs | Long-term balance and sludge reduction |
Why Choose Granular Endothall?
- Dual-purpose control: One granular treatment can address algae and many submerged weeds in the same site.
- Cleaner placement: Granules are easy to target around docks, shorelines, coves, and spot-treatment zones.
- Better planning: The label gives ppm, acre-foot, and 1,000-square-foot depth-based rate structure for more confident sizing.
SKU: NTBIO3744336
UPC: 724235263626
Category: Algaecides, Herbicides
Brand: UPL
Weight: 20 lbs
Dimensions: 24 x 12 x 13 in
SDS: View Safety Data Sheet (PDF)
LABEL (Directions & Rates): View Product Label (PDF)
Comments/Other: Review the Product Label and SDS for directions, rates, and safety information.
Certifications / Registrations: EPA registered
Origin: Locally Manufactured, Made in the USA
Feature: Granular formulation for targeted application, Ideal for spot treatments and shoreline management
Product Form: Granular
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Reviews
Verified Purchase
To knock out Chara I apply this and follow up with Reward. Works every time!
Verified Purchase
I used The hydrothol and cutrine granules to take down our stubborn Chara and they both work great together. I followed up with nt-max for the dead chara and muck and polish up with black dye. Looks very nice now.
Verified Purchase
We use Hydrothol granular pellets on two large ponds at our corporate park entry gate. It works well and lasts all year with 2 treatments, followed up by NT-MAX fuel digester and the dark blue dye. Good prices.
Verified Purchase
Killed the underwater weeds in about 14 days! Easy.
Verified Purchase
Put this along the dock and killed a nice path about 20 feet out. Works as described.
Verified Purchase
This product is perfect. We have a big gathering coming up end of summer and had massive weeds all around our area of the lake. Hydrothol worked amazing and the shoreline looks really good!
Verified Purchase
Weeds turn brown after 14 days.
Verified Purchase
For the last 3 years we have been fighting Curly Leaf weed and this product killed in it two weeks where others failed. Granular is easy to apply.
Verified Purchase
Applied on a Saturday and most weeds dying or gone by Friday. Great stuff!
