• Gus Hetcher

Testing Your Waters

Influenced by nutrient loading, sedimentation and other factors, ponds are an ever-changing system. These changes can take years to be observed or can happen within days. Often, we notice changes to our pond when something drastic occurs, such as an algae bloom or a fish kill. Many times, these drastic events are indicative of poor water quality. Poor water quality can lead to excess plant or algae growth, fish kills, bad smells, health concerns and ponds looking like an “eye-sore”. This is why it is important to regularly test the water in your pond. There are many parameters that effect water quality. A few of these parameters include alkalinity, ammonia, chloride, dissolved oxygen, hardness, nitrate, phosphorous and pH.

Alkalinity is a measure of the amount of carbonates, bicarbonates and hydroxide present in water. Alkalinity is determined by soil and bedrock characteristics. Ponds fed by groundwater from limestone aquifers tend to have high alkalinity. High alkalinity is often associated with high algae and aquatic plant production. Ponds with low alkalinity are usually susceptible to acid rain.

Ammonia is a nitrogen compound that is produced by microbial decomposition of organic matter. Ammonia is rapidly converted to nitrate in the presence of dissolved oxygen. Sudden increases in ammonia may indicate pollution from fertilizers, manure or septic systems and may be toxic to fish and other aquatic organisms at high enough concentrations.

Chloride occurs naturally in lakes and ponds and may fluctuate seasonally with runoff patterns. At normal levels, chloride is not toxic, but at high levels it can be toxic to aquatic life and may indicate contamination from septic systems, fertilizers, animal wastes or road salts.

Dissolved oxygen is one of the most important parameters in aquatic ecosystems, as most aquatic organisms depend on dissolved oxygen for survival. Despite aquatic plants producing oxygen through photosynthesis, the most important source of oxygen in lakes and ponds is atmospheric diffusion. Since oxygen diffuses into water rather slowly, mixing through wave action or current is essential for oxygenation of water. Because ponds are smaller bodies of water and usually lack wind fetch, they are more susceptible to oxygen depletion or anoxia. High plant or algae production, or heavy nutrient loading can also lead to anoxia. Most common fish species require concentrations of at least 4 mg/l for survival. Very few species can survive less than 2 mg/l. When anoxia (< 1 mg/l) occurs at the sediment layer, phosphorous is released from the sediment – fueling algae blooms. Toxic gases such as ammonia, methane and hydrogen sulfide are also released from bottom sediments under anoxic conditions.

Nitrate is a nitrogen compound that is important for plant growth. Nitrate plus ammonia concentrations exceeding 0.3 mg/l may lead to nuisance algae blooms. Nitrate concentrations exceeding 10 mg/l pose a health risk to infants and expectant mothers. High nitrate levels may indicate pollution from fertilizers, animal wastes or septic effluent.

Phosphorous is an important nutrient for plant growth. Phosphorous concentrations are commonly the limiting factor in plant production in aquatic environments. Thus, even small additions of phosphorous to a lake or pond may cause dramatic increases in plant and algae growth.

pH is the negative logarithm of the hydrogen ion concentration. pH serves as a ready indicator of the acidity or basicity of water. A pH of 7 is neutral. A pH less than 7 is considered acidic and a pH greater than 7 is considered basic or alkaline. Preferred pH ranges for most fish species is 6-8, with few surviving below 5.

The biologists at Cason & Associates understand having good water quality results in a clean and healthy pond. By testing your water for these parameters, we can design a management plan specific to your pond’s needs. By utilizing our nutrient management products such as beneficial bacteria and enzymes to promote bacterial growth to absorb excess nutrients, phosphorous reducing agent to lock and bind excess phosphorous, and other products, we can help you achieve a cleaner and healthier pond

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