Experienced aquarists know how important the water quality is in the aquarium. You can determine exact values using various tests. You should do this at regular intervals regardless of your impression of the aquarium. But also by simply observing your aquarium you can assess and find out whether a more precise control of the water is currently useful. The following signs will provide you with valuable insights.
Fish on the Surface
If your fish swim on the surface and gasp for air, that’s an alarm signal! Your water quality is likely so bad that your fish will no longer be able to breathe properly. Ammonia poisoning is often to blame for this. Ammonia damages the gills. As a result, the fish can hardly take up oxygen from the water. In such a case, you should do a 90% water change quickly and continue normal partial water changes over the next few days. Also, stop feeding for 3 days. In the following week, watch your fish particularly carefully, check the water parameters and the technology, especially the filtering. Also, check to see if the pool is “bogging” somewhere: a dead fish or spurned food pollutes the water considerably. Excessive fish stocks can also cause such problems.
Turbidity in the Aquarium
If the aquarium water is cloudy, this can have various causes. The suspended matter is to blame, but what is it? First, observe whether the suspended solids sink after a while, then it was probably just dust (for example from the substrate) and you do not necessarily have to test your water. If the cloudiness does not go away, it could be a bacterial bloom or infusoria. With so-called bacterial blooms, bacteria multiply very quickly in aquariums. It can be completely harmless and good filter bacteria, but also potential pathogens. In any case, you should check the water quality in the aquarium, because the explosive growth suggests a disturbed water balance. The same applies to a strong infestation with infusoria. These are unicellular animals such as amoebas, flagellates, and ciliates (e.g. paramecia). They also often occur as a result of bacterial bloom.
Diatoms in the Aquarium
Do you have brown deposits on the stones and panes of your aquarium? That could be diatoms. They are usually slightly rough to the touch and difficult to remove. From this, you can see that a special parameter is likely to be very high in the water: the silicate value. Silicate (also spelled silicate) usually comes into the aquarium via tap water. It doesn’t harm the fish. But the diatom needs silicate for its cell envelope and grows rapidly when a lot of it is available. This can be extremely annoying. The silicate value cannot be determined with conventional test sets or strip tests. A special test is required for this. If the value is higher, it is advisable to remove silicate from the water using special filter media. Then you will quickly get rid of the unsightly diatoms.
Scum on the Surface of the Water
Sometimes you can see thin, milky, cloudy skin on the surface of an aquarium. This is usually caused by bacteria that multiply on the surface of the water. This phenomenon can often be observed in freshly set up and not yet safely run in aquariums. So it speaks for unstable water quality in the aquarium. Therefore, it is better to test the aquarium water if you make such an observation in a tank that has already been retracted. If necessary, it can help to create more current on the water surface. This is often very easy by changing the position of the filter vent a little.
The skin can be colored differently. It has to do with the type of bacteria. Mostly it’s just whitish. If cyanobacteria also play a role in their formation, they can also appear greenish to bluish.
Air Bubbles on Plant Leaves
It can sometimes be seen, especially in good lighting: Small air bubbles form on the plants and grow slowly. When they have reached a certain size, they rise to the surface of the water. If you look closely you can see that they get smaller again on the way there. This has to do with the fact that the gas is dissolved in the water. What you can observe there is called photosynthesis. With the help of light energy, the plant converts carbon dioxide from the water into oxygen bubbles that are visible here. Your fish can breathe the oxygen. If you can make this observation, it suggests that there is a lot of carbon dioxide in the water. This is very good for the plants. But be careful: too much carbon dioxide harms your fish!
Assess the Water Quality in the Aquarium
As you can see, it is usually not difficult to see how the water quality is in the aquarium. You don’t have to be an ace in chemistry to do this, just keep an eye on your pool. Nevertheless, we recommend that you test the water at regular intervals. The most important values, the concentration of which you should definitely check about once a week, are nitrite, nitrate, the pH value, and the water hardness (total hardness and carbonate hardness). In addition, the values for ammonium, chlorine, and copper can be relevant for keeping animals in the aquarium water. If you attach great importance to beautiful plants, pay attention to the water values of the nutrients carbon dioxide, iron, magnesium, and phosphate. It is advisable to create a table for a better overview. You can enter the most important water values in this. If you have measured for a while, you can better assess developments. And thus rather prevent one of the above-mentioned phenomena of poor water quality from occurring at all.