Don't expect to have clear water in spring

(unless you use a lot of chemistry - which we do not recommend)

	Important: Using bacteria to change water quality will not be much effective until water is about 15-20 C. Hence the typical  problems with  the water transparency  in spring. The state has to be tolerated or non-bacterial means used.
	simple self-made filter water is pumped from the pond  into the inlet (left side) the water passes through the tube filled with sand and bacteria. The water runs out to the right - back to the pond The tube filter is filled with the sand and bacteria are added. (add bacteria with some water and wait for about 2 hours before starting the pump) The water throughput for this filter  not too high. The amount of water running freely through this filter is roughly 100 l per hour.
	STEP III
	Finally, after converting ammonium into nitrate an issue of utilization of nitrate arises. If nitrate is not used by "nice" plants, typically algae will grow, resulting in "dirty" greenish  water.
	So what should we do? - planting water plants will help.
	Usually buying a lot of plants will be very expensive if your pond is large. One solution is to propagate the plants in a small warmer pond (for example, covered by transparent plastic cover)  or at home  in early spring time .
	Potamogeton natans
	Polygonum amphibium

In Austria some of the plants you can order from Greinegger Wasserpflanzen