Normally northern ponds don't need aerated as long as southern ponds, but there are lots of exceptions to that generalization. Southern ponds usually have warmer water for longer periods compared to northern ponds. Warmer water holds less dissolved oxygen thus in these warmer ponds the the lower saturated DO is lost and consumed quicker and oxygen shortages can happen relatively quick especially on extended cloudy days. Aeration helps increase the DO at all mixing depths. Southern ponds tend to benefit more with 24/7 aeration compared to northern ponds - many exceptions occur.
Esshup's comments are wise, heed them. Sizing of an aerator system is very important. Oversizing a pond aerator is easier and more effective in smaller ponds, thus shorter run times are possible. That is one key factor in allowing shorter run times. Oversizing rarely occurs in larger ponds 1.5 acre+ thus those aerators need to run longer to get the WHOLE pond of several million gallons turned over in one day. Aerator mixing volume and pond volume are important factors in getting a proper sized aerator. It is not just about putting some bubbles in the pond. In larger ponds or small ponds with under sized aerators, often one complete pond turnover per day is not achieved nor possible, thus the aerator needs to run 24/7 to keep the mixing as much as possible. In a small 1/3 acre pond with a high air flow aerator and efficient diffuser the pond of 500,000 gallons can be turned over in 3-5hs thus a short run each day time is possible. Not so true in a large deep pond or small lake.
Water clarity also affects how long the aerator needs to run. The cloudier or murkier the water the more the aerator needs to run each day because less sunlight is penetrating the water and less dissolved oxygen is being produced by suspended planktonic algae in the depths below sunlight penetration. Mixing spreads out, blends, and distributes that dissolved oxygen to the darker, deeper waters. Ponds need dissolved oxygen in the deep waters to keep everything them them healthy -oxygenated. Without a steady supply of oxygen at the pond bottom all bottom and deep water critters start dying quickly even in summer unless a turnover from aeration brings them fresh oxygen.
Last edited by Bill Cody; 04/03/12 07:22 PM.
