The water seems to be staying clear and whilst it is a bit green in tone there is nothing like algae, just reflections off the mud at the bottom. The robot still has not arrived to clean this up. In the meantime I have been going round with a shrimping net to clear any flotsam off the surface - leaves and such like. Horrified to see though millions of tiny wriggling insect-like creatues in the deep water zone. I took a look inside the box which houses circulation pump and it was completely jammed up with dead insects - too small to be caught by the skimmer. I have now to go and clean the pump chamber every few hours. Another email to the Expert - this time he takes a while to reply. The insects are probably dragonfly larvae - you ought to leave them to develop, but if you can't bear that then put in a trout which will eat them up..... Oh no, have I been killing dragonflies! Better let Nature take its own course from now on.