spc - Generally and almost always your pond does have PLENTY of dissolved oxygen(DO), but during the main part of the summer that DO is confined ONLY to the upper 6'-7' in a typical one acre pond in the Midwest. Water below (6'-7') that is devoid of DO esp after early to mid June. The separating layer is called a thermocline, maybe you have heard of it. This concept is called stratification. Rarely, exceptions do occur and numberous things contribute to stratificaion and destratification throught the summer.
Last edited by Bill Cody; 02/19/09 08:58 PM.
