Potassium hydroxide

Potassium hydroxide (KOH) is a white pellet, very alkaline substance used to raise pH without altering the GH or KH of the water in an aquarium. It rapidly dissolves in water to supply potassium (which is used by plants) and hydroxide ions which combines with H+ ions to produce H2O (water) so increasing the pH.

Take care

 * When added to water it will react by producing a lot of heat. So care must be taken never to add it directly to the aquarium.
 * This chemical is harmful if swallowed or will burn if it comes in contact with the skin.


 * Never adjust the pH by more than 0.4 in 24 hours for an existing aquarium with livestock. Otherwise pH shock may result.

Other names
Caustic potash, Potash lye, Potassia, Potassium hydrate.

Availability

 * Commonly available on eBay and in various gardening shops.

Links

 * Wikipedia - Potassium hydroxide
 * eBay - Potassium hydroxide