Copper sulphate: what use, what danger?Available in drugstores, copper sulphate is generally in solid form. It is used for its fungicidal and bactericidal properties. He thus enters the composition of the Bordeaux mixture. This component of the ”  Bordeaux mixture  ” is a copper salt that exists in two forms: anhydrous (SO 4 Cu), white and pentahydrate (SO 4 Cu, 5 H 2 O) forming crystals of a beautiful deep blue. Copper is not attacked by sulfuric acid. It is the attack of copper carbonate by this acid which produces the copper sulphate according to the reaction. This reaction is carried out in copper tanks and the crystals are fixed on copper bars. The crystals of several centimeters of a very beautiful blue are then recovered and finely crushed in particles of 1 to 3 mm of pale blue color: this is what is found in the trade in the form of ”  copper sulphate snow  .

Copper sulphate in Bordeaux mixture

The dose of copper sulphate required for the preparation of the Bordeaux mixture  (a pesticide that fights mushrooms) depends on the plants to be treated. The generally accepted dose is 200 g per 10 liters of Bordeaux mixture. Note that the copper sulphate must first be diluted in 2 liters of water. The slaked lime is prepared separately, using 400 g of lime for 4 liters of water. Once these two solutions are made, they can then be mixed by adding 4 liters of water. The Bordeaux mixture must rest a day before its application.

Copper sulphate in for the maintenance of a swimming pool

Copper sulphate is used to prevent or treat the formation of algae in a pool. The treatment is done only at the beginning of the season or just before the winter, in order to avoid any risk for the swimmers (because attention, danger …). The dosage of copper sulphate is one half gram per cubic meter. In the case of particularly dirty swimming pool water, the dose can however be increased to 1 gram per cubic meter

The dangers of copper sulphate

Copper sulphate is toxic. Inhalation, ingestion or simple skin contact, it causes violent reactions. It is therefore recommended to use it with care and to equip gloves, protective clothing and a mask to handle it. In addition, copper sulphate dissolves in water: its use around a lake or watercourse is therefore prohibited, in order to avoid any risk of pollution.