Hi Monica,

The chlorine in the bleach doesn't stay active long(less than a day). Mosquito control people use some kind of oil. The oil keeps the larvae from breathing air when they wiggle to the surface. There are anti-mosquito tablets available for ponds that are a time released control. Sounds like a good idea to find out where the water is coming from. Good luck Aloha

Thanks! I didn't know about those tabs or the oil for mosquitoes. I'll definitely look into that :) And as soon as I can pull DH off his current project long enough, I'll have him drain the valve box and see if it fills up when we turn the sprinklers on.
Monica

Hi monica,

The state or county vector control agency can tell you what type of oil they use. They might even give you some to control mosquitoes. The oil is the best and longest lasting control, I believe but the vector control people would know the best ways and means. Aloha