Vinegar will drop your pH value of your water greatly. Do a water change! I would also add carbon and would reposition your powerheads to flow at the top of your tanks air/water surface interface to continually transfer out carbon dioxide and replenish depleted dissolved oxygen!
Good luck!
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I go by parrothead on associatedcontent.com to search for other articles by myself, by the way if anyone is interested!
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What Does Oxygen Have to Do with My Marine Aquarium!
We all know how important oxygen, here on earth, is with regards to the plethora of living organisms that require oxygen and would not be able to function without it, ultimately death would be the final outcome. Their are ways of having too much dissolved oxygen in tank water, or not enough. Proper ways to maintaining optimal levels as close to the saturation point for dissolved oxygen can be incorporated very easily into any aquarists daily ritual. Optimal oxygen levels and the maintaining of this crucial component as close to the saturation level is exemplary.
I will present ways of focusing on oxygen and affording you the tools to ensure your oxygen level is ideal. What negative ramifications can be seen, under less than optimal dissolved oxygen within a marine aquarium will also be discussed.
Oxygen that is present in water is called dissolved oxygen or DO for short. Oxygen enters the water via various ways. The transfer of oxygen and carbon dioxide (CO2) across the air-water interface being the main source. As oxygen enters the water, carbon dioxide is removed. The air-surface interface is nothing more than the waters surface at the top of your tank. There are three main ways for oxygen to be replenished in an aquarium. The presence of a powerhead or other device causing a rippling effect across the waters surface will help to ensure that a steady influx of oxygen is generated into your aquarium. Another way that oxygen can be added to your tank is by incorporating algae or other plant life which will provide beneficial oxygen through photosynthesis. The last way is through the use of a protein skimmer(foam fractionator) and/or air stone/air pump combination. The creation of micro bubbles provided by the skimmer and air pump will also aid in the formation of oxygen within the confines of your aquarium.
The amount of oxygen that water can support is dependent on three key variable: water temperature, salinity and atmospheric pressure. The amount of oxygen that water can hold is called its saturation state. The solubility(maximum amount of a solute to be dissolved in a solvent at equilibrium) of oxygen , in this case oxygen being the solute and water being the solvent, varies.
In terms of the solubility of oxygen in water, oxygen increases in water as the temperature decreases. Therefore as the temperature of water increases, the amount of DO in the water becomes less. The solubility of oxygen also decreases with a raise in salinity. This means that freshwater holds more oxygen than salt water and as the salinity of the water goes up the amount of oxygen will continue to decrease. The last scenario can best be depicted in terms of the elevation in which one lives. The higher the elevation one lives, the less likely their water is to retain oxygen due to relative pressure. The oxygen transfer rate can be defined as the amount of time required for the DO to reach saturation. For instance, given a normal salinity and temperature and an aquarium at sea level, the oxygen level at saturation is roughly 5mg/L. Supersaturation or water with excess dissolved oxygen is normally evident in coral reef biotopes, so the oxygen level is normally at 7-10mg/L during the daylight hours. Hence, this brings about two very distinct scenarios. Water that is deprived of beneficial oxygen carries with it, the problematic fact that fish and other living organisms may become stressed or suffocate in extreme condition with prolonged exposure to these dangerously low oxygen levels. At the other end of the spectrum, water that contains too much DO, or a supersaturated level of oxygen in the water, may cause corals, anemones and other livestock, containing zooxanthellae, to bleach and eventually die due to the abundance of oxygen generated by the zooxanthellae. This is often times accomplished by intense light that is too strong for corals, Tridacna Clams or anemones, causing the host zooxanthellae to work very hard to compensate for the strong lighting.
The two scenarios coincide hand in hand with the daylight and nighttime hours. During the day, light is the strongest and also is the time frame with which aquarium lights are on. With this comes the possibility of supersaturation and problems with photosynthetic animals. For fish and other livestock it also brings about a higher level of DO aiding the fish and other various livestock that consumes oxygen in the water column. Nighttime brings about the opposite situation. Supersaturation often is negated by the darkness within the confines of an aquarium helping the corals, anemones and other zooxanthellae containing animals. For the fish, bacteria and other living organisms, this time presents the chance of respiration reducing the amount of DO in the water and the possibility of suffocation. Those with a deep sand bed will experience this more so than by those maintaining aquariums containing 1-2 inches of substrate or less. This can be taken a step further. In the presence of a power failure, aquariums with a deep sand bed will find their Do level will become depleted at a quicker rate than by those that do not have a thick substratum. Larger fish will become affected before smaller fish. Also, newly acquired fish will be more prone to problems dealing with lower dissolved oxygen level than fish that have been in a tank for some time as it seems their tolerance level has been elevated over time in a captive environment.
OK, so the moral of this story is to be aware of the changing parameters that effect your aquariums oxygen level. Minimizing your fish population as well as the presence of larger fish. Implementing a strong protein skimmer and air pump complete with an air stone will add beneficial oxygen to your water. Creating water disturbance at the air-water interface by incorporating a powerhead, surface skimmer and/ or powerfilter creating a cascading water flow, will help to replace carbon dioxide with oxygen. A refugium set on a reverse daylight time pattern housed with macroalgae can add oxygen to your tank at night when photosynthesis has stopped due to the shutting off of your lights over your main tank. Maintaining a lower temperature and salinity level as well as not housing a glass top over your tank will further enhance your tanks ability to establish an appropriate oxygen level. Your livestock will reap the benefits of an ideal amount of oxygen and offer you and yours many years of beauty, entertainment and fascination.
Desperately Seeking Help 
jb
