Carbon Water Purifiers
Some domestic supplies are now dosed at the water treatment works with an excess of chlorine to fight any possible bacterial infestation within the water supply system.
Any residual chlorine left at the tap may then cause serious harm to fish in your pond and should be removed. This can be achieved by passing water through a bed of Granular Activated Carbon, (G.A.C) during a contact period of one minute.
Certain drinking water supplies have also become contaminated with other potentially harmful substances such as chlorinated hydro carbons which derive from various pesticides, herbicides and some industrial solvents. G.A.C will effectively remove these but only if the flow rate is reduced to provide contact of 4-5 minutes.