Clean and clear aquarium water: A guide to water quality and management
Also see: Cure and prevent cloudy or green water
Water may appear clean and clear but, actually, be absolutely toxic to your fish. You need to be able to create water that is clean and healthy for your fish. Below I will explain how to create clean and clear water and how to maintain this indefinitely by establishing a balanced ecosystem. It can be said that you are not taking care of your fish but rather you are taking care of the water the fish live eat and breathe in.
A fully-functioning aquarium is a balanced ecosystem that needs to remain balanced in order to let your fish thrive. Setting up and maintaining this ecosytem is the first and most important step towards taking good care of your fish.
In order to understand how to successfully manage your aquarium water, you need to become familiar with the various attributes of water that aquarists generally deal with. The water in your tank will have more in it than simple H20, and frequent testing is the best way to keep all of those additional elements in check. Some of the attributes and chemicals worth paying attention to follow:
- Temperature – your water needs to have a controlled temperature for your fish to survive. Tropical aquariums are typically heated to a temperature between 23–28° C (74–82° F).
- pH level – This is the measure of your waters acidity, and is affected by its hardness. Certain fish have pH requirements determined by their natural habitat, but a range somewhere between 6.5–8.2 is the norm.
- Hardness – The amount of dissolved minerals in your water contribute to its hardness. Soft water generally carries a lower pH level. Most fish are tolerant of moderate hardness between 100–250 mg/l.
- Chlorine and chloramine – These chemicals are added to municipal reservoirs to keep your tap water clean and safe to drink. They are toxic to fish, however, so you will need to remove them from your water. Chlorine will evaporate on its own if left to sit for a few days, but chloramine requires the use of a water conditioning product to successfully remove.
- Phosphate and other minerals – These are substances that are usually ignored by most aquarists. But there are times when it is necessary to test for other substances. Such as when algae becomes a persistent problem or plants are not growing.
- Ammonia – Ammonia is toxic to fish and is caused by decomposing waste, and the point of your aquarium filtration system is to remove harmful ammonia by converting it into nitrite and then nitrate. That takes place during the nitrogen cycle, which will be covered in more detail below. The optimal level of ammonia in your water is zero. Anything above .25 mg/l of ammonia means you need to perform a water change.
- Nitrite – A secondary element of the nitrogen cycle, nitrite is not as toxic as ammonia, but it reduces the ability of your fish to oxygenate their bloodstream. A normal tank should not have more than .5 mg/l of nitrite. If it does, it is time for a water change.
- Nitrate – The end product of the nitrogen cycle’s chemical conversion. Not as harmful as nitrite or ammonia but still harmful in high doses. Nitrate can be tolerated at levels up to 40 mg/l.
Cycling your aquarium water
Since substances like ammonia and nitrite are toxic for your fish, you need to remove them from your water on a continually. Fortunately, once matured, your filter will automatically remove them for you. Your aquarium’s filtration system is designed to host a range of beneficial bacteria that convert ammonia into nitrite, and nitrite into nitrate; a process called the nitrogen cycle. In order for that to happen, however, you need to set up your aquarium for cycling.
Since fish produce ammonia, they are typically used as the beginning point of the nitrogen cycle. After being added to a tank, very frequent water changes are needed to keep the fish healthy until the bacterial colony which feeds off the ammonia has developed sufficiently. Fishless tank cycling can be achieved using pure ammonia, as well.
Once ammonia is in the tank, bacteria will naturally show up to begin consuming it and converting it into nitrite. This can be speeded up by introducing a working filter from another aquarium, since a colony of bacteria should already be present established there. If this is not an option, then they will develop, on a new filter, slowly over 30-60 days. A secondary layer of bacteria will also appear that will convert the newly created nitrite into nitrate.
The end result of growing these bacterial colonies in your aquarium filter is that your water will essentially be recycling its own waste. However, nitrate still needs to be reduced through partial water changes. Luckily, that is only a weekly task. If you are keeping fish in your tank while cycling, you will need to perform large daily water changes until the ammonia levels fall to near zero.
Setting up a water management routine
Once your tank is properly cycled, you will still need to monitor your tank’s water. Since the nitrogen cycle is taking care of your immediate concerns over waste matter recycling, you can keep your water quality high with minimal effort. The only daily task that is necessary at this point is checking the water temperature.
Weekly tasks include performing a small water change, between 10–25%, as needed according to the nitrate level of the tank. You should also be testing your water every week in order to gauge the nitrate level as well as detect and prevent any possible ammonia, nitrite, or pH problems that may spring up, before they get serious.
Your monthly tasks should include a vacuuming of the tank gravel, a squeezing out of the excess dirt from your filter sponge and a scrubbing to remove any algae present in the tank. Never use tap water on your filter sponge. Squeeze out the sponge using some water from the aquarium. This avoids harming the beneficial bacterial colony growing on it.
Common water quality problems
One of the most evident signs that your aquarium water has a problem is if the smell changes. Aquariums generally have a pleasant lakeside scent to them once they are properly cycled, but excess ammonia and other elements can change that, giving you a warning to test the water and change it quickly.
Most often, bad-smelling water is a sign that there is too much waste in the tank as a result of overfeeding. Your fish should generally eat all of their food in two minutes or less and not leave any to rot. Excess food will rot which releases excess ammonia that will poison your fish. Occasionally your fish will go off their food. Feeding at this time will just result in food being left uneaten and rotting. Remove any uneaten food using a siphon.
A fish that dies in the tank should be removed immediately. A rotting fish will release a lot of ammonia which your filter will not be able to cope with.
Algae is another common result of poor-quality aquarium water. Again, excess nutrients (especially nitrate and phosphate) can allow algae to bloom, turning your water green and presenting problems for your fish. If you are not overfeeding your fish, then algae may bloom because of an excess of yellow light. Also, be sure to keep your aquarium out of direct sunlight.
If you pay attention to your water and follow the guidelines mentioned above, you should have a tank full of clean and clear aquarium water for your fish to enjoy.