Check your filter and pump. Clean or replace any filter material. We carry replacement media for most pond filters. If you have a UV filter, lamp efficiency declines with age and use. It should be replaced annually, each spring, before it goes out. Just because the UV light is on, it does not mean you are getting any benefit from it. We carry service kits, parts and UV Bulbs for many of the name brand UV filters. If you are thinking about adding a UV filter, the Pondmaster UV can be used both submerged and out of pond. They are easy to install, come in 10w , 20w, and 40w, and you will see a dramatic difference in your water clarity.