I have an approximately 100 gallon front yard pond with no heater. We have had sporadic goldfish -- nothing else, really. We have a UV filter but now having a horrible green algae problem -- are there any algae eaters that can live outside with no heater? Temperate climate -- northern California...

Is this suspended or attached algae? The UV should kill the suspended. If it's not, it may need a new lamp. Attached algae in small amounts is a good thing. If there's too much, try trapdoor snails, barley straw, adding lots of plants, a bigger filter, etc. Plecos can live in a pond if the water is above 55-60 degrees F but I think Northern CA gets colder, right? My pond algae page has more information if you haven't been there yet. Good luck!

http://www.fishpondinfo.com/algae2.htm

IF YOU HAVE NO PLANTS IN YOUR POND ADD COOKING SALT OR SEA SALT IT IS GOOD FOR THE FISH 100 GALLONS = 50 OUNCES = 1.5 KG