I do have the diffuser in about the 10' range. The water has never been crystal clear but that could be because the pond is clay lined. I use blue dye. Last year I used a floc log and introduced pond bacteria and that really helped to clear the water but that gets expensive. I'm looking at an used 1/3 hp Gast aerator on ebay, do you think that would be too much for the size of my pond? I thought about saving the linear pump for the winter when I move the air stone to shallower water, because I figure less air is needed then and it runs cheaper. Do you think there could be a shock factor to the fish with doing this? Thanks, Ken