How (and How Often) to Test Aquarium Water for Healthy Fish and Plants
Regular water testing is vital for keeping tabs on the health of your aquarium fish and plants, but most beginners in the fishkeeping hobby are not aware of the importance of this practice. People can clean out an aquarium if it is dirty-looking. Aquarium water is actually made up of invisible waste chemicals that are derived from fish poop. These compounds can pose a danger if they are too high. Test kits are the only way to accurately measure if your water is clean and safe enough for fish and plants to live in.
How to Test Water in a Fish Tank
There are two types of water testing that fishkeepers can use: (1) test strips and (2) kits that include test tubes or small containers. A chemical reagent is mixed with a sample of aquarium water and changes color based on the water parameter being measured. After a time period, the reagent can be compared to a chart to show the final results. Here are the most common parameters we recommend looking at:
1. Ammonia: Ammonia is produced by your fish and invertebrates from their waste. It is extremely toxic to animals, especially in water that has high pH. Keep it at 0ppm (parts/million). Measure it with the Ammonia Test Strips.
Aquarium Co-Op Ammonia Test Strips
1. Nitrite: In a mature aquarium that is cycled, beneficial bacteria consumes the ammonia and produces nitrite. Nitrite is also toxic to animals and can burn fish gills and skin, so keep it at 0 ppm. Measure it with Multi-Test Strips. 2. Nitrate: In a mature aquarium, another type of beneficial bacteria consumes nitrite and produces nitrate, which is less toxic to fish. We recommend that nitrate levels are kept below 50 ppm as a rule. If you have aquarium plants, they consume nitrate as food, so we like to maintain at least 20 ppm nitrate to keep them healthy. Measure it with Multi-Test Strips, and read our nitrate article to learn more. 3. Chlorine: If your drinking water comes from a municipal water supply, then most likely it is disinfected with chlorine or chloramine to eliminate pathogens. These chemicals can cause death in animals so it is necessary to use a dechlorinator to ensure safe drinking water. To make sure your chlorine is at 0 ppm, measure it with Multi-Test Strips.
Aquarium Co-Op Multi-Test Strips
1. pH – pH is a way to tell how acidic or base the water. The pH range of most freshwater fish is between 6.5 and 8.0. However, some species prefer a lower or higher pH. It can be measured with multi-test strips or the API High Range Acid pH Test Kit.
API pH Test with High Range
1. GH: The General Hardness (GH), which measures how hard or hard water is, is measured either in dGH or ppm. For freshwater aquariums, we recommend that you keep between 4-8 and 70-140ppm of minerals. It can be measured with Multi-Test Strips and the API GH & GH Test Kit Combo. 2. KH is Carbonate hardness (KH). This measures the water’s buffering ability. The higher the KH, the less likely the pH will rapidly change, which can be dangerous to fish. It is measured in dKH or ppm (degrees of KH), and for freshwater aquariums, we recommend that it be kept at least 3 dKH or 50 ppm to avoid pH swings. It can be measured with Multi-Test Strips, or the API GH & H Test Kit Combo.
API H & KH Testing Kit Combo
1. phosphate: Phosphate (or phosphate) is a macronutrient which plants need to grow. But, excess phosphate can harm fish health and cause algae growth. While every aquarium has its own fish and plant stocks, there are guidelines. Some hobbyists suggest 0.5-2ppm phosphate in low light tanks, and 3ppm or more in high light aquariums with CO2 injection. Measure it with the API Phosphate Test Kit.
API-PHOSPhate Test Kit
1. Copper – Invertebrates can be sensitive to trace amounts of copper in water. However, some medicines contain copper to treat specific fish diseases. To determine the amount of copper in tap water, or to administer copper-based medications to sick fish, use the API Copper Test Kit.
API Copper Test Kit
1. CO2 The Dennerle CO2 Quick Test can be used to determine the amount of dissolved CO2 in an aquarium. To determine if your tank has enough CO2, fill the test tube half way with water. Then, shake the tube for a while and compare it to the chart.
Dennerle CO2 Quick Test
When and How Often to Test Aquarium Water
Water should be tested every day. However, in the past, testing kits were expensive and time-consuming. Fish keepers might overlook something unusual in their tanks and not test the water. Aquarium Co-Op test kits were created to be easier and less expensive so that you can test more often to ensure your peace of mind. Here are the most common circumstances in which we recommend testing your water:
1. New Aquarium It takes time to cycle an aquarium to ensure that the biological filter is mature enough to remove toxic waste from fish. It is vital to test the water daily while the aquarium is being cycled. This will ensure that the levels of ammonia, nitrite and nitrate are not too high. You can get the Multi-Test Strips or Ammonia Test Strips. If you get consistent safe and repeatable results, you can reduce testing to every three days. Then, test once a week. Finally, test once a month. For more information on aquarium cycle, read our full article.
1. Tank Maintenance After your aquarium has been cycled, you will only need to use the Multi Test Strips once every 2 weeks to check for nitrate levels. Nitrate can be toxic at extremely high levels. We try to keep the nitrate level below 50ppm. If the nitrate level is between 75 and 100 ppm, it’s time for a water change. One of the main reasons we keep live plants within our aquariums is to help reduce the need for water changes. You can use our water chart flow diagram to determine how often water changes should be made based on your nitrate reading.
1. Missing Fish If any of your animals show signs or are acting strangely, you should check all parameters to determine the cause. Start by checking the water temperature, Ammonia Test Strips, and Multi-Test Strips. If you suspect an abnormal increase in pH, use the API High Range pH Test Kit. Copper is more dangerous to invertebrates, such as snails and shrimp. The API Copper Test Kit can help you check the water quality. It is important to determine whether the measured values are within a safe range and to also evaluate if they are significantly different from what you have previously seen.
Fish health problems can arise from sudden changes in water parameters.
1. Unhealthy Plants When balancing the lighting and nutrients in a planted aquarium, nitrate is a key component to keep an eye on. Multi-Test Strips can be used to determine the level of nitrate in the aquarium. Keep it at 25-50ppm. If the nitrate levels fall below the recommended level, you may need to use Easy Green all in one fertilizer to replenish the nutrients. If there is an excess or a shortage of phosphate, it can cause algae growth or leaves with large holes. The API Phosphate Test Kit will help you determine the situation. The Dennerle CO2 Quick Test can help you determine how much dissolved carbon dioxide is in your aquarium if you’re adding phosphate gas to it to boost plant growth.
1. Outside Pond Large outdoor ponds with large amounts of water are best tested using the Ammonia Testing Strips and Multi-Test Strips at least three-to-four times per year. At the beginning of summer, we want to see how the water fared over the winter. Check the water quality in the middle of summer. The fish have been eating different foods and the pond evaporates more quickly during warmer weather.
At the end of pond season, make sure all the water parameters are safe before preparing for the cold weather. Finally, it may be good to do an extra test in the middle of winter to see how the fish are doing.
Water test kits can be used for both aquariums and outdoor ponds.
The more mature and problem-free a fish tank is, the less frequently we tend to test it, but don’t forget that your aquarium is a living ecosystem and things are constantly changing. You should test your aquarium again if you travel, change fish food, buy or sell fish, add or remove plants or make other changes to the tank. Many hobbyists keep track of water parameters over time by keeping them in a notebook or spreadsheet. For a fish room with multiple tanks, our CEO Cory will mark the results down on blue painter’s tape and stick it directly on the aquarium glass.
To learn more about water chemistry, we’ve gathered a series of articles to help you increase your knowledge and enjoyment of the fishkeeping hobby. Check them out and enjoy nature daily!