Algae and Nitrogen in your Water Pond

Algae and Nitrogen in your Water Pond

Water ponds are beautiful, but we need to keep the algae from making our ponds ugly. In the spring, microscopic algae often flourish, giving way for green water. Green water offends the pride and spoils the enjoyment of many fish keepers who may have to buy a biological filter to clear up the water.

The largest constitute of algae is chlorophyll, which oxygenates the water in the presence of light but de-oxygenates it in the dark, sometimes leaving insufficient oxygen for the filter bacteria before dawn. Some of the filters are in-suffient in green water.

Experience has shown that a reduced dosage of either the freeze-dried or live bacteria preparations applied to the filter system every morning when dissolved oxygen levels are rising can clear a pond in ten to fourteen days. Continually replacing the bacteria after a few hours of warmth during daylight hours, they will gradually become established.

Interestingly, green water is usually indicative that the filters are functioning perfectly. Green water can be very beneficial to koi. This will enhance the color patterns of small koi and providing essential nutrients to newly hatched fry. On Japanese koi farms, green water is encouraged in the fry ponds with the addition of large quantities of manure.

Nitrate poisoning is responsible for more mysterious disease and deaths than any other disturbance. Symptoms take up to three weeks once the koi have been exposed. Large Koi may respond to excess nitrate in the water by lying on their sides and are generally lethargic. They will continue to feed, however small koi will probably die.

Testing water conditions regularly while new filters are becoming established, after the winter when mature filters are becoming fully operational once again, or following some other disruption, will enable you to monitor any dangerous increase in nitrate levels. Reducing or even withholding food from koi in order to limit the ammonia production is one way of minimizing potential damage. You can also add zeolite to the filtration system and this will extract surplus ammonia.

In cases of high nitrate levels you may need to change as much as thirty to forty percent of the water daily. If the nitrate level is extremely high, you can neutralize it to some extent by adding salt to the water. This will discourage many parasites and bacteria growth. You should not add salt to the water if you have already added zeolite in the filter. This will release ammonia back to the water.