Do I need a protein skimmer?
How important is it to have a protein skimmer? What is the impact of high levels of proteins in the water and are they harmful to the koi?
The visible impact of high levels of “proteins” is excessive foaming of the water at the waterfall and aeration points. That is then also the method employed to remove with a protein skimmer. Foaming due to waves breaking at the beach results in the same process of removing these compounds.
Not necessarily only proteins, but also sugars and other organic molecules arising from the food given, the excrement and dead organic matter of all kinds accumulating in the pond. The tell-tale foaming being due to the long-chained carbon molecules mostly of lipid origin.
This is also referred to as DOC, Dissolved Organic Compounds, although many talk about Dissolved Organic Carbons, which is a misnomer since organic implicitly refers to a chemical of carbon origin. Also, not necessarily soluble in the true sense of the word, but they are there in low concentration, sometimes coalescing into an oily slick drifting on the water surface.
Over time these organic compounds build up in the water and normally get diluted by regular pond water changes, however if you are feeding at a high rate, your pond may suffer the consequences.
What are these?
These bits and pieces of organic molecules are the natural food of a host of heterotrophic microorganisms like protozoa, fungi, yeasts, and bacteria. They act like vacuum cleaners keeping the house clean, which is fine while their numbers are kept in check, but if you are feeding at a high rate, their population can explode. Now you are ready for a perfect storm. All the fish needs is a stress condition.
Some of these organisms are opportunistic by nature, they may eat anything, but will also eat the rich slime of the fish, and if they can overcome the natural defences of the fish, you have disease. Once these organisms break the skin, they have a field day. Infected gills and ulcers. Bacteria inside breaking down the living tissue, a protective layer of fungi on top mopping the rest.
There are also a second detrimental consequence. The oily layer interferes with the natural oxygen-water exchange process and in certain scenarios will cause an anoxic condition. Additional aeration and turbulence will counter this potential threat.
What to do?
That is why you should keep the DOC low. To keep the bacterial count low of your pond water to prevent disease outbreaks. And that is why many people use an antibacterial like AntiBac, potassium permanganate or PPM, or peroxide regularly to chemically keep bacteria count at bay while others use a protein skimmer, or some just a large water change. Sterilising UV tube properly installed will also control the organism load.
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