TMC Pro Pond UV ~ Pond Clear works by halting the reproduction of algae. The
ultraviolet lamp is sealed inside a quartz sleeve. As water is pumped through the
unit, ultraviolet light from the lamp destroys the green, single celled water borne
algae (which makes garden ponds murky and unattractive), will leave the water crystal
clear. This has no adverse effect on sensitive plant and pond life.