Today the Water Authorities produce water in the purest form - they remove many of the problems by introducing Chlorine to remove bacteria and they introduce many other products to ensure that the water we use from our taps poses no threat to Human Health .... and for that we must be grateful.
But... this same 'High Quality' water is probably one of the deadliest substances to our valuable Koi. The Chlorine that protects us is Poisonous to our Koi and the Nitrate levels contained in raw tap water can affect our Koi.
Mains water direct from the tap contains Chlorine and many over hard metals, these are not healthy or productive for a healthy and balanced nitrogen cycle in our ponds.
The most effective means for water purification for a pond it is best to allow for very slow flow rates through a dedicated pond water purifier system. The longer the water takes to pass through the purifier, the greater the benefits of the purification system.
A flow rate of one to two gallons per minute should be more than adequate to help remove any nasty impurities, and the water can safely be added directly into your filtration system or the pond.