Question:
UV doesnt sterilize pond water. It aint gonna happen. The sun is pouringUV rays down on the pond and all bodies of water and it only enters an inchor so and doesnt sterilize anything. Most living things hang out on oraround the greenery in the pond, and that sure aint going thru the UVfilter.

Answer: Well, Ingrid, I think you should call your local water treatment plant and askthem if UV light will sterilize water. I think you may be surprised by theiranswer. (that is, of course, if they use UV to purify their water.) Hospitals,Water treatment plants, anyone needing large amounts of sterile water, they alluse UV light. The UV light we receive from the sun is nowhere near as strongas that produced by a UV unit. The sun has the atmosphere to filter out mostof the UV it produces. All UV units have very strict warnings as to lookinginto them or exposing your skin to them and this is the reason why. Normally,I would capitulate to your experience, Ingrid, but on this I can't. I havedone much research on this subject even before I got into ponding. (severalBiology projects on water treatment and purification).