The sulfur could be in the clay bottom of the pond. If your water PH is low and stays low I bet it is in the clay bottom. The best way to remove sulfur from water is to spray it into the air with a fountain. This will degas sulfur fast and should not return.

I control our pond water temp with our aeration. We run it at night and it will cool the pond down. We shut it off around 10am let the top 30"s warm but for the depth of the pond it out numbers the gallons that are warm. When learning we run the air 24/7 in the summer and did see the pond up here in Ontario get to 85 and the perch just stopped eating. It was like they were not even in the pond.

Bill tipped me off on running it at night to control water temp and it works like a charm. Cuts the FA growth, and keeps the fish feeding more. Swimming is still nice in the top but dive down or pull water from below up with your feet and its cold!


[Linked Image from corvettejunkie.com]
http://www.pondboss.com/subscribe.asp?c=4


7/8th of an acre, Perch only pond, Ontario, Canada.