Evening pic of said pond.Ordered a W model which hopefully will be with me today. This will go in my small 800litre pond. I bought it secondhand for a good price. Looking forward to putting it in. I already have a pond filter with 9w UV doing a good job of keeping the water clear. The W should add that extra sparkle to the water. The ponds only been set up 6 weeks and doing very well. We do have issues with herons here but I have 2 deterrents a trip wire and a rotating scarer. There was a heron in the garden which approached the pond but I inadvertently scared it off when I would have just liked to observed it. However it seems I have lost no fish to herons so hopefully that will continue to be the case.