Water in a newly constructed pond is usually muddy, but water can also be muddy in old, well-established ponds too. In new ponds, water turbidity should clear up as a good sod cover grows on the exposed soil around the pond. However, several things may contribute to a new or an old pond’s muddy water, all of which can be cured through simple pond management techniques. These are erosion in the watershed, fine clays in the construction site, certain fish such as bullheads, livestock within the pond area, and the action of wind on the shorelines.
First, the cause of the problem should be determined. If removal of the cause is not effective, one of several chemicals may be tried. The broadcasting of 1,000 pounds of ground agricultural limestone (calcium carbonate), 740 pounds of hydrated lime, 1,000 pounds of agricultural gypsum, or 250 pounds of aluminum sulfate (commercial alum) per surface acre is effective in clearing many muddy ponds. These materials will help suspended solids to bond together, settle to the bottom, and clear muddy water.
The first two chemicals should clear the pond and keep it clear up to two years. With gypsum it may be necessary to treat several times a year. In some cases, where the turbidity is caused by an excessive growth of microscopic organisms, periodic spray applications of copper sulfate at two pounds per surface acre have proven effective. No matter what has caused the off-color water in your pond, proper pond management can help you, your pond, and your fish.