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Hydra Crystal

Hydra Crystal
Product + Price Qty

Removes Green Water and Algae from Ponds with External Filter Systems to give Crystal Clear Water.
NOTE: This product is only to be used in conjunction with an external filter box.


  • Rapidly clears green algae in water
  • Simple and easy to use
  • Fast visible results
  • Safe for humans, animals and aquatic life
  • 100% Biodegradable
  • No negative effect on water quality
  • Longer lasting results
  • Harmless on concrete and synthetic liners and to biological filters or pumps

How to Use

  • Simply dose Hydra Crystal at pump outlet, broadcast over pond surface, or dilute with water and add as a slurry. 

  • UV lights can be left on during treatment.

NB. Very heavy green water may require two applications.    

Initial Dose for Badly Fouled Water

 1 Heaped spoonful (blue spoon in tub)

 Treats 100 gallons

 1 ounce

 Treats 93 gallons

 8 ounces

 Treats 750 gallons

 28 ounces

 Treats 2,600 gallons

 8 pounds

 Treats 11,900 gallons

 40 pounds

 Treats 59,500 gallons


Cannot see your fish? Troubled by murky green water in your garden pond?

Hydra Crystal clears green water from ponds with external filter systems to give crystal clear, clean water. It is harmless to all fish and aquatic life and does not persist in the environment. A lovely pond can be a source of inspiration and pride. Whether you are a commercial grounds keeper or a home pond owner you know algae can cause your pond to look green and ugly. Typically algae growth, odor emissions and sludge build up in lakes and ponds is a result of a biological imbalance and flocculation (small single cell algae spread out across the surface of your pond).

Excess nutrients in your water from sunlight, overfeeding of fish can cause algae to bloom and turn your cherished, clear pond water into pea soup! To stop this from happening in the first place, we recommend dosing your pond with a bacteria treatment. This re-balances the bacteria: nutrient ratio and ensures that nutrients are not able to build up in the first place. Too late for preventative measures? Do not worry, Hydra Crystal will remove the algae from your pond and once it is clear you can use Hydra Bio Aquatic Boost to stop the algae from coming back.

Hydra Crystal has continuously and successfully clarified murky and green pond water, removed pond algae and impressed thousands of customers worldwide.

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Registered address: Hydra International Ltd,Cerberian House,Carters Lane,Kiln Farm,Milton Keynes,MK11 3ER, UK.
Company Registration Number: 2983464 - Company Registered in England UK.