Controlling Biological Levels in the Tank

Controlling biological growth in rain water tanks is one of the most important aspects of rain water harvesting if the water is to be used for human consumption. There are a few ways of doing this, the two main methods are dosing a sanitizing agent or circulating the water through a UV light. The problem with dosing is that you need to remove what you added, for example chlorine before the water is consumed. This is where a UV light system is nice; it leaves no residual traces in the water. Ideally you want at least two tanks; one for the rain water to top up and another that is kept clean and constantly circulating through a UV system. The first tank should feed the second via sediment filtration and a UV system; this will give you a tank of usable water with little need for more treatment.