The average reefer has several tests to keep track of important parameters of their tank, but oxygen saturation is often overlooked due it's difficulty of testing. In fact because of it's difficult to measure nature, it's often overlooked and not even thought about, but it is very important and can play a key role in the health of your fish.
Let's get started with the way O2 saturation works in reference to several other conditions in a reef. First is altitude. This one is not hard to figure at as it's common knowledge that at higher altitude there is less oxygen, and this also means that the maximum saturation of water at altitude is lower. Less commonly known is the relationship between salinity and temperature to O2 saturation. The high your temperature and the higher your salinity the lower your maximum saturation level.
Let's look at some numbers.
At an elevation of zero, temperature of 77 and salinity of 1.021 there is a maximum of approximately 7.047 mg/L of O2 in the water.
When we move up to an elevation of 5280, Denver, with all other parameters the same saturation drops off to just 5.804 mg/L. This means water hold about 18% less oxygen just by moving up to Denver's altitude!
Now let's see what happens when we change salinity a little bit. We will start with the same parameters as we had in Denver but bump up salinity to 1.025. This gives us a maximum saturation of just 5.609 mg/L. This constitutes a drop in O2 of about 3% and a drop from our first sea level number of almost 21%!
Now for all you high temp reefers out there let's see what happens with the temperature climbs. We'll start with the last numbers at an altitude of 5280, salinity of 1.025 and up the temperature to 81. This give us a saturation of just 5.399. A further drop of almost 4% and a total drop from the first numbers of about 23%
These are pretty substantial numbers which show that the higher altitude you live at and the higher you wish to keep your salinity and temperature, the more you need to pay attention to replenishing the oxygen in your water. Skimmers and water flow should be all important to people in the higher risk altitude zones and for those that wish to have higher salinity. These numbers are nothing to panic about and fish have been thriving in them for many years, but it must be noted that with lower numbers such as these there is less for your fish to consume before it can become an issue.
It's common knowledge that fish need a certain level of oxygen to live in an aquarium, but what is not commonly known is that there is such thing as too much. Supersaturation is the term for having too much O2 in your water, and it is the primary cause of gas bubble disease. Fish can also live well in higher saturation levels, but it is when they are placed in highly saturated water too quickly that problems can arise. Fish who fall victim to this will usually develop pop eye and their gills will show massive trauma. Onset is fast and usually fatal for most fish.
So what does this mean for how we should keep our fish? As the numbers would show, doing a water change with room temperature water that drops your water from 81 to 77 degrees quickly would bring saturation up 4% and lowering salinity from 1.025 to 1.021 would bring saturation up by 3%. While these numbers aren't huge, they should be enough to convince most people to put a heater in their water before doing a water change and keep their salinity as stable as possible.
If you are interested in more reading on this topic, Jay F. Hemdal's book, Advanced Marine Aquarium Techniques, is a great place to start.
Let's get started with the way O2 saturation works in reference to several other conditions in a reef. First is altitude. This one is not hard to figure at as it's common knowledge that at higher altitude there is less oxygen, and this also means that the maximum saturation of water at altitude is lower. Less commonly known is the relationship between salinity and temperature to O2 saturation. The high your temperature and the higher your salinity the lower your maximum saturation level.
Let's look at some numbers.
At an elevation of zero, temperature of 77 and salinity of 1.021 there is a maximum of approximately 7.047 mg/L of O2 in the water.
When we move up to an elevation of 5280, Denver, with all other parameters the same saturation drops off to just 5.804 mg/L. This means water hold about 18% less oxygen just by moving up to Denver's altitude!
Now let's see what happens when we change salinity a little bit. We will start with the same parameters as we had in Denver but bump up salinity to 1.025. This gives us a maximum saturation of just 5.609 mg/L. This constitutes a drop in O2 of about 3% and a drop from our first sea level number of almost 21%!
Now for all you high temp reefers out there let's see what happens with the temperature climbs. We'll start with the last numbers at an altitude of 5280, salinity of 1.025 and up the temperature to 81. This give us a saturation of just 5.399. A further drop of almost 4% and a total drop from the first numbers of about 23%
These are pretty substantial numbers which show that the higher altitude you live at and the higher you wish to keep your salinity and temperature, the more you need to pay attention to replenishing the oxygen in your water. Skimmers and water flow should be all important to people in the higher risk altitude zones and for those that wish to have higher salinity. These numbers are nothing to panic about and fish have been thriving in them for many years, but it must be noted that with lower numbers such as these there is less for your fish to consume before it can become an issue.
It's common knowledge that fish need a certain level of oxygen to live in an aquarium, but what is not commonly known is that there is such thing as too much. Supersaturation is the term for having too much O2 in your water, and it is the primary cause of gas bubble disease. Fish can also live well in higher saturation levels, but it is when they are placed in highly saturated water too quickly that problems can arise. Fish who fall victim to this will usually develop pop eye and their gills will show massive trauma. Onset is fast and usually fatal for most fish.
So what does this mean for how we should keep our fish? As the numbers would show, doing a water change with room temperature water that drops your water from 81 to 77 degrees quickly would bring saturation up 4% and lowering salinity from 1.025 to 1.021 would bring saturation up by 3%. While these numbers aren't huge, they should be enough to convince most people to put a heater in their water before doing a water change and keep their salinity as stable as possible.
If you are interested in more reading on this topic, Jay F. Hemdal's book, Advanced Marine Aquarium Techniques, is a great place to start.
