Got a murky pond? Here are standard procedures pond doctors use to diagnose the source.
The first step is determining if murkiness is caused by activity in or around the pond. Is there a large population of carp, catfish, or other bottom feeders fanning up sediment? Are livestock frequently wading in the pond? Is wind action stirring sediment as waves roll across shallow flats? Or, is the condition caused by clay soils at the pond site?
Conduct a “sediment test” by collecting a pond sample, preferably in a one-gallon glass jar. Place the container in a dark space for one week. When retrieving the jar, closely observe improvements in clarity and sediment on the bottom. If there is significant clearing, it’s assumed the source is among above sources. If there is no change in murkiness, unfortunately the problem relates to negative-charged clay particles in the soil. Those particles suspend in the water column and are inhibited from settling to the bottom.
Two common methods to improve clarity are treating with Ag gypsum or aluminum sulfate (alum). Alum produces fast results, but MUST be used by an experienced applicator. Improperly applied, alum may cause a sudden spike in alkalinity and kill fish. Please follow treatment procedures to the letter.
Gypsum is a safer product. To determine the correct amount, collect four, one-gallon glass jars of pond water and one jar of clear water. Leave one pond water jar as a control. Mix two level tablespoons of powdered gypsum into the clear jar. Stir into a “slurry”. Add the slurry into the three remaining samples–one tablespoon at a time. Each tablespoon represents approximately 80 pounds of gypsum per acre-foot of water.
Put one tablespoon in the first jar, two in the second, and three in the third. Wait at least 12-hours. Evaluate differences between jars. If there is no change, add another round of the slurry until of the jars clears. Convert the number of tablespoons required to achieve clearing into the total pounds of gypsum for treatment.
Neither treatment is a guaranteed, permanent fix, but will improve clarity. Original conditions could return with the next significant influx of runoff into the pond.
