- Fast-Acting Granular Formula
- Great For Bottom Growing Algae & Chara
- Control Weeds Surrounding Docks & Shorelines
Hydrothol® 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.
|Square Footage Per Container
||Up to 8,000 Square Feet
Hydrothol To Treat Algae
Hydrothol To Treat Chara
Hydrothol To Treat Weeds*
|1,000 Square Feet
||7.5 - 25 Pounds
|2,000 Square Feet
||15 - 50 Pounds
|4,000 Square Feet
||30 - 100 Pounds
|8,000 Square Feet
||60 - 200 Pounds
*Use on aquatic weeds is dependent on weed type and density.
Please note: Above are recommendations. Always read the product label.
How To Apply
Broadcast Hydrothol® onto the area to be treated using a granular spreader. Treat only up to half of the pond's surface and wait 10-14 days before a second treatment. During hot weather or when treating heavy growth, it is important to treat no more than ¼ of your pond at a time and wait the full 14 days before re-applying. This helps lower the risk of fish loss during hot weather or when treating heavy growth. Once it is completely dead, use a rake, like the Pond & Beach Rake, to remove dead algae away to prevent an accumulation of dead algae and muck.
When To Apply
Hydrothol® should be applied when algae and weeds are actively growing. Begin applications when algae and weeds first appear. Unless steps are taken to reduce the overall nutrients in the pond, multiple applications may be needed for full season algae control.
- Wait 7-25 days before using treated water for human drinking water.
- Wait 7-25 days before using treated water for livestock and domestic animal consumption.
- Do not use in ponds with trout, unless carbonate hardness is above 50ppm.
- Do not use in ponds with koi, grass carp or goldfish.
- Not for use in water garden or koi ponds. Please click here for water garden and koi pond algae control options.
Chemical Application Best Practices
Anytime you use chemicals to treat algae or weeds, please keep in mind the following:
- Treat your pond in sections. Treat only half the pond's surface at a time. During hot weather or when treating heavy growth, it is important to treat no more than ¼ of your pond at a time and wait the full 14 days before re-applying. This helps lower the risk of fish loss during hot weather or when treating heavy growth.
- Once the algae or weeds have browned & died, use a rake to remove as much dead material as possible. This prevents an accumulation of dead plant material and muck.
- Take a proactive approach to pond management. Use PondClear™, MuckAway™ and Pond Dye to keep your pond looking great. For more information, see our article on the Airmax® Ecosystem™
Here are the replacement parts for Hydrothol ® Granular Aquatic Algaecide & Herbicide.
The first step towards effectively treating any pond weed is proper identification. Hydrothol® Granular Aquatic Algaecide & Herbicide is recommended for use against each of the weeds listed below. Click on your desired weed for more information and alternate control options.
Curly Leaf Pondweed