What is responsible for the condition of your ponds water? The most obvious answer to this question is the screens and filter pads found within your mechanical filter. Though this is partly true, it is equally important that your biological filter is active. Channeling your pond water through the nitrifying bacteria of the biological filter is how we are able to control the level of ammonia in your pond. As organic materials such as leaves and fish waste decompose, they produce ammonia (NH₃/NH₄⁺). This product is toxic to fish, and is the reason for your biological filter. The bacteria found within this filter will convert the ammonia to nitrate (NO₃^-), thus turning the toxin into plant food! Plants use this nitrate for protein, and therefore are required for this system to work. If the amount of plant material is not sufficient in handling the level of nitrate in your pond, then particulate or "green-water" algae growth may result. Typically, 50-60% of your pond should be consumed by plant material to avoid the growth of particulate algae.

Another important aspect of your ponds water is its salt level, or salinity. Fresh water lakes and streams etc. still contain a certain level of salt. The salt is necessary, in moderation, for the health of your fish, as it keeps the electrolyte count up in the pond water. This helps fight against infection as well as replenishes the fish’s slime coat. A fish’s slime coat is their first line of defense against disease and parasites.

A third important aspect of water quality is its acidity or pH level. Most natural waters have pH values between 5.0 and 8.5. As plants take in CO₂ for photosynthesis, pH values (and alkalinity) rise. Aquatic animals have just the opposite effect, and will lower pH values (making the water more acidic). For this reason, it is important that the acidity of your pond stay somewhere in the middle, at a neutral 7.0. High pH can make it difficult for aquatic plants to uptake nutrients from the water. And low pH can create stress situations not favorable for fish. Yet, perhaps the most important consideration for your pond’s pH level is from runoff and replenishing. Whether from rain or from your home, new water in the pond will altar your water quality. This is yet another advantage of owning a larger pond. Smaller ponds hold a lesser volume of water, and may change its pH level with a minor amount of rain. Larger ponds however, are much more resistant to change and would require several inches of rain for the same change in acidity (during an even longer period of time).

Your best bet against water quality problems is to monitor the condition of the water using test kits. The most valued kits will be Ammonia, pH, and Salt level test kits. The information found using these kits simply couldn’t be determined without them!

Maintaining An Ecosystem