A Ship(wreck)’s Log IV: Life Support Systems
An essential part to a successful aquarium.
Hello again and welcome to a Ship(wreck)’s Log. Things are really starting to heat up around here. We are now just a few weeks away from opening; the aquariums are in place, the exhibit construction is almost complete, most of our fish are in quarantine, and we have water in our tanks,but they are not quite ready for the fish.
In this post I am going to tell you about the next step before placing the animals in their new homes. That step involves life support systems and Aquarium conditioning.
You may be able to keep a fish in a tank of water for a brief period, but sooner or later these fish are going to have needs to be healthy. Like us, fish need to breathe. Unlike us, who use lungs to get oxygen to our bodies, fish use gills. A container of water will have a little bit of oxygen but the fish will use it up pretty quickly and we will have to replace it. We will have to regulate the temperature, since fish are cold blooded the temperture of the environment is very important. If we leave our water out too long it may become too cold or hot for the fish. The fish are going to get hungry and going to need eat, and as we all probably know what goes in must come out. These wastes will need to be removed from the water. Fish waste includes solids and nitrogen. One form of nitrogen is ammonia, and at very low levels ammonia can be very harmful to our fish.
Now since we know that long term housing of our fish in the tank will not work let’s explore how we will make it work. This is done using the life support system.
Life support is another way of saying aquarium filtration. We call it a life support system because this system makes the aquarium environment able to support life by removing waste and adding basics to the water like oxygen.
The first step in keeping our fish is a tank or aquarium. Our aquarium will hold water and, like our own homes,will have furniture to make the aquarium more comfortable for the fish ( more to come on that topic in the next post).
Next is the movement of water. The water has to flow from the aquarium to the life support system and back to the aquarium. This is called recirculating. In order to do this we use a pump to move the water and pipes for the water’s path.
As water fills the tank skimmers at the top of the tank draw water out, down to the sump and life support system. The sump is basically a large tank. The splashing of the water into the sump adds the oxygen and is where the pump pulls water from and pushes through the rest of the life support system.
The next step in our life support system is waste removal. As I mentioned earlier there are two types of waste that need to be removed; solids and nitrogen. To remove solid waste we use sand filters. The sand filters are large vessels about three quarters filled with a special type of sand. As the water flows through the filter the sand traps the solids much like a colander would trap spaghetti, and let the now solid-free water move through.
The nitrogen removal is a bit different. Here we need help from bacteria, or more specifically, nitrifying bacteria. These bacteria will remove harmful nitrogen (ammonia and nitrites) through a process call nitrification. The end product will be a less harmful type of nitrogen (nitrate) that can be removed by water changes. We do have a specific filter for this called the bio-filter. A bio-filter is basically a vessel that will promote bacteria growth by giving the bacteria a place to grow and thrive. One type of bio filter that we will use is called a fluidized bed. This filter is somewhat like a sand filter in that it is a vessel partially filled with sand, but this sand is not used to collect solids. The sand is for bacteria to grow on and the water flows through for the bacteria to come in contact with the nitrogen in the water.
Since these fish will be tropical we need a way to heat our water so the next step will be a heater. We will be using a heater called an in-line heater, where the water will flow past a heating element on its way back to the aquarium.
We can now safely keep our fish alive with this system. But since we are an aquarium, and we would like you to see the fish we add a couple more special filters to the life support system to ensure that the water is crystal clear.
Though our sand filter is taking out the larger solids, smaller solids we call organics (which usually consist of algae) will be slipping through and making our water cloudy or green. So we use two types of filters to take care of these very small solids. These filters are a protein skimmer and UV filter.
The protein skimmer is a filter that creates very small bubbles. These bubbles act like “magnets” which the organic particles will stick to. As the bubbles collect the solids they create a grimy foam that is lifted out of the water by the bubble action into a collection chamber. They are then removed from the system.
The UV filter is a vessel that has ultra violet (UV) lights in it. The UV lights will destroy the cells of these organics. The broken down organics will begin to stick together, and are now big enough for our sand filters to remove them.
Our Life Support systems have all been installed, the pumps are running and water is in the tank. But we are still not ready for the fish. Now we have to condition our tank.
Previously, I mentioned that we have a bio-filter where bacteria will remove harmful nitrogen. Well, conditioning our tank means we are culturing bacteria. This naturally-occurring bacteria will already be in the water but we need to promote it’s growth by “feeding” it. We start by calculating how much nitrogen our fish will produce. The type of nitrogen the fish give off is called ammonia nitrogen. We then add the ammonia to the water using a powdered form and test the water. We know that the process is started when the amount of ammonia in the water drops as we are still adding it. As the ammonia numbers are dropping the byproduct of this process is nitrite. So as the ammonia drops, nitrites will rise. Nitrites also can be harmful to fish, but lucky for us there is another bacteria that will remove nitrites and the byproduct of this process is nitrates. Nitrates are less harmful to fish and can be managed by regular water changes.This whole process can take up to four weeks. So our first priorities we have when putting in a new exhibit is making sure that our bio-filters are up and running.Currently we are in the middle of this process, but the conditioning is almost complete and we plan to start adding fish soon.
A healthy life support system is the most important step in keeping healthy happy fish. Next time you are at the aquarium and you see the fish swimming by, I hope you will have a better understanding of what goes on behind the scenes to keep things swimming.
The next post we will explore putting the “ship” in Shipwrecks Alive!