Water testing - what to look for

In this article I will try and provide some information about water testing. Other than the apparent health of the inhabitants of your aquarium, water testing can give you a good idea of the quality of the water, and also help you detect potential problems that may eventually lead to disaster. Before I begin, let me first address the issue of water changes. Regardless of the type of aquarium you have, I recommend that you consider doing water changes every two to three weeks. During each water change, it is a good idea to remove about 15% of the water. Doing so will help ensure that you have a healthy aquarium, and should be adequate to maintain healthy levels of bacteria in your aquarium. Below I will list several types of water tests that you should consider doing to keep an eye on your aquarium. I have listed the water test types in two separate section. The first contains test for all aquariums, and the second if for only saltwater and reef aquariums.

All Aquariums

Nitrate - I have not listed ammonia and nitrate in the list here, but I have included nitrate. As those of you out there who understand the nitrogen cycle of aquariums know, ammonia and nitrite are common in new aquariums that are being set up for the first time. Assuming that your aquarium is already established, ammonia and nitrite levels should be at zero. Nitrate is a final product of the nitrogen cycle, and as a result accumulates in all aquariums over time. One exception to this is in well maintained reef systems. Nitrate can be consumed in reef aquariums, however in all cases nitrate levels should be kept below about 10 PPM. Slightly higher levels are tolerable in non-reef aquariums, but I still recommend that you try and keep levels not much higher than 10 PPM. Nitrate levels can be easily reduced by water changes. If you find that the typical 15% water change every two weeks is not sufficient to keep nitrate levels below 10 PPM, you should consider increasing the volume of the water changes.

Oxygen - I do not personally check the oxygen level in my aquariums since I am fairly confident about the filtration and aeration of my systems. There are cases in which you should consider testing for oxygen content. For example, if you notice that the fish in your aquarium are breathing more rapidly than usual, or they are constantly skimming the surface, this may be an indication that there is insufficient oxygenation in the water. For this type of water test, I recommend that you only check it as necessary.

pH - pH should be measured on a monthly basis. This is about every other water change. It is a good idea to measure the pH at the same time of day since the value will tend to fluctuate some throughout the day. Typically a pH of about 8.3 is desired. You can live with values between 8.2 to 8.4 - pH values outside this should be compensated by adding calcium hydroxide. This should be added as needed, and can be found at all local fish stores.

Phosphate - Most aquarists that I have come across do not have a good idea of why phosphates are important to monitor. The truth is that phosphates are a great source for algae growth. If levels begin to rise in your aquarium over time, you should consider increasing the volume of you water changes. One of the side effects of not keeping up with water changes is the increase in phosphates in the aquarium (as well as unwanted nutrients), and this can quickly lead to algae problems. There are also a few products that you may find in the store that will reduce phosphate in the aquarium, so you may want to check this out if you find that you have a problem with phosphate levels.

Saltwater and Reef Aquariums

Salinity - As you can guess this is only something you keep an eye on in saltwater or reef aquariums. Both water evaporation and water changes will influence the salt content in the water, and so I recommend that you check the salinity of the water on a weekly basis. The salinity of the water is easily checked using a specific gravity meter. The salinity of salt and reef systems should be maintained at 1.022 to 1.024. The range is due to the fact that salt content in the water will be temperature dependent, and thus it will tend to fluctuate throughout the day. One should measure the salinity of the aquarium every time water is added to the aquarium, weather for a water change or to replace evaporated water. Doing so will allow for you to compensate with the water to be added to the aquarium.

dKH - The carbonate hardness of the water in your aquarium can be a good measure of the alkalinity of the water. Carbonate hardness is the protection of the aquarium from changes in pH. Carbonate hardness should be kept with a value between 8 and 12. Such levels are very healthy for your aquarium, and can be easily maintained using regular additions of Kalkwasser, and by doing regular bi-weekly water changes. Carbonate hardness should be measured every month.

Hopefully you have gained a little insight about the several types of water testing that you can do to check the quality of the water in your aquarium. There are several other test types, but I feel that those above are the most important ones that you should keep an eye on. If you are not sure of how to check for such levels in the aquarium. Visit you local fish store and ask for a test kit. Most test kits will provide tests for the above. Keep in mind the meaning of each, and make sure that you keep track of the measurement results over time for comparison.