On my opinion ,the level of dissolved oxygen ranks among the most important components as far as water quality is concerned. Oxygen is the elixir of all life form occupying some 21% of our atmosphere.Being slightly soluble in water,its presence ensure our fish continual existence and it is our responsibility to ensure adequate as well as continual supply are given to fulfill this need.This article highlight the various conditions that may deplete dissolved oxygen in your system and methods that you can overcome the shortfalls.

Situations which may bring about O2 depletion

1) water temperatures are high especially in the tropics and summer months
2)the stocking densities are too high .Needless to elaborate
3)there is a lot of organic matter in the system because organic matter consumes substantial amounts of dissolved oxygen when it decomposes
4)there are large amounts of submerged plants and algae, because they remove oxygen at night and their presence cover the surface of the water, thereby reducing the surface area available for oxygen exchange.
5)Failure to ensure adequate circulation across the tank or pond
6)Add oxygen-consuming medications like formalin, potassium permanganate, or 0.6% salt during hot weather. .
7)Underperforming biofilter, with restricted flow to it, or use medications which kill the nitrifying bacterial within. As ammonia and nitrite levels rise, the fishes oxygen uptake mechanism becomes impaired.
8)Presence of ammonia in a cycled pond.

In short either there is a substantial decrease in the availability of dissolved oxygen or else there is some form of impairment in the uptake of it at the gill/water interface

For water to be enriched with oxygen there should be:ยท

Some movement. By splashing through waterfalls, spraying through spray-bars, pumping air by means of air pump through the water, employing venturi return, any form of agitation to the water/air surface, we expose a substantial percentage of the fluid and air exchange which will oxygenate the water. As the water near the air/water interface is saturated with oxygen, it needs to be moved out of the way to allow more water to be regenerated. This is what moving water is all about.

Secondly for exchange to be feasible there must be a higher oxygen pressure on the atmospheric side of the air/fluid interface than there is within the water itself. Once water reaches its saturation point, it cannot hold oxygen anymore. That is why you need adequate circulation to move enriched oxygenated water away to allow O2 depleted water to absorb the atmospheric oxygen.

Thirdly utilizing oxygen releasing agent like hydrogen peroxide and commercial preparation like oxypur may enable instant O2 introduction whereby we can use in times of emergencies but never view them as long term solution to frequent O2 depleted set-ups.

Although in well aerated water system,oxygen depletion is very unusually encountered,Hopefully the above article will remind us of its importance and significance.It is my hope that you are able to dissolve or resolve any doubts arising from the issue on dissolved oxygen after reading.



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