UNDERSTAND YOUR POND SYSTEM – THE NITROGEN CYCLE.

Bernard Iha.

UNDERSTAND YOUR POND SYSTEM – THE NITROGEN CYCLE.

The entire world has been practicing fish farming since time in memorial and significant evidence can be drawn from the egyptian civilization with little ruins of what could have been royal pond s filled with all manner of fish species for food – perhaps in trying times along the timeline feud of the Israelites and the egyptian pharaohs. Recently, there has been a major shift towards this practice and in Kenya alike a number of people have been able to corageously tread in its waters. Today, I would wish to talk about our pond health. How do we ensure that we breed high quality species and in the same manner ensure maximum commercialization. The whole idea of a fish pond or tank is to replicate the natural ecosystem in every manner. One important thing we need to remind ourselves is that all ecosystems have a way to sustain themselves naturally to ensure that no organism within lacks any primal need. In science we call them supporting, and regulating services. When we talk about fish and health the significant service that should pop in our minds is the ‘nitrogen cycle’ and needless to say I believe most of us – through the 8-4-4 system were made awre of a thing or two. A natural fish environment will never miss the nitrogen cycle, lest it collapses. We then have to ensure that this occurs in our various pond systems and here are how and the reasons why. The cycle begins with the fish itself during feeding period. We may feed our tilapia, catfish or tuna several feeds including skretting – like humans the fish shall produce wastes. After gaining the enough energy to live, the rest of the feed is converted to ammonia. In a natural setting the ammonia is broken down to nitrite and then nitrate which in turn is taken up by plants through conversion to the earlier nitrogen in plants. How do you ensure that your pond goes through all these processes. Here is what we have done at aquablue fish farm.

After feeding our fish with floating feed we understand that they will excrete and produce ammonia. Amomnia will exist only in two forms in water – free ammonia which is highly poisonous and ionized ammonia whis is not as harmful. High levels of ammonia, above 0.25 ppm should alarm you. Otherwise 0 ppm is encouraged. We need to break down this ammonia and so we need the nitrosomonas and nitrobacter bacteria that will convert NH3 to nitrite an then nitrate respectively. We have done these through creating a media platform within which bacteria can build up in and as water moves through the bacteria have a chance to convert the ammonia. The media could be just anything onto which the bacteria can hold on to including, bio-balls, porous stones and plastic material. As the water comes out of our filtration system we notice that too much algae forms in the pond and this is a clear indication that there are high levels of nitrate. Too much algae in the pond would eat out the necessary oxygen that would otherwise be utilised by the fish – so what we do is allow some of the water from the biofilter pass through separate tanks within which we have floated plants that would take in some of the nitrate and returning low-nitrate water back into the pond.

We welcome you at our farm for an in depth description of how our pond system works and how we can increase pond and filtration efficiency.

Welcome.