I live in the north of Portugal, and we have a water 'mine' which runs into a 'pool' area that is partially painted and has several huge pieces of local granite rock in it. It is of uneven depth, from maybe just a few inches to thigh height. The water pours in and out at a balanced speed through a spout, FAST, as we have undone the drain to allow the water to flow through constantly, as we do not want to get any nasty midges or worse laying in it! The surface is moving too, as the water falls into it from the spout. Unfortunately for the algae situation it is in full sunlight! Our friend who owns the property wants this to be a 'paddling' type pool with no fish etc. We can empty it, scrub it clean and then once the water flows in, it fills within an hour and a half - and within two weeks, has green algae all over the bottom and sides and attached to the rocks. Some is just a millimetre or two in height... and some... is like that long seaweed - up to three feet long !!!
As the water has to flow out constantly, adding the 'dreaded chemicals' seems impossible anyway - but does anyone have an idea of what we can do to stop this ??
