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 can contain invisible waste chemicals, such as fish poop, and other compounds that could be harmful at dangerous levels. The only way to determine if your aquarium water is safe and clean enough for plants and fish to drink is with test kits.
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. Mixing a small amount of aquarium water with chemical reagent will change the color depending 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 some of the parameters we recommend:
1. Ammonia: Ammonia is produced by your fish and invertebrates from their waste. It can be very toxic to animals in high pH water. The recommended level should be 0 parts per million. Measure it with the Ammonia Test Strips.
Aquarium Co-Op Ammonia Test Strips
1. Nitrite In an older aquarium that has been cycled, beneficial bacteria eats the ammonia and makes nitrite. Nitrite can also be toxic to animals. It can cause severe burns to fish’s skin and gills. Keep it below 0 ppm. Multi-Test Strips can be used to measure it. 2. Nitrate Another type of beneficial bacteria will consume nitrite in mature aquariums and produce nitrate which is more toxic to fish. We recommend that nitrate levels are kept below 50 ppm as a rule. Aquarium plants eat nitrate, so we recommend keeping it below 20ppm to ensure their health. To find out more, use Multi-Test Strips to measure it. 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 are deadly to animals and must be removed from the water supply. To make sure your chlorine is at 0 ppm, measure it with Multi-Test Strips.
Aquarium Co-Op Multi-Test Strips
1. pH: pH tells you how acidic or basic the water is. While most freshwater fish can survive at pH levels of 6.5 to 8.2, some species prefer pH levels that are lower or higher. It can be measured with multi-test strips or the API High Range Acid pH Test Kit.
API High Range pH Test
1. GH General Hardness (GH) is a measure of how hard or soft water is. It is measured in either dGH (degrees GH) and ppm. Minerals are essential for healthy animal and plant growth, so we recommend keeping between 4-8 dGH (or 70-140 ppm) for most freshwater aquariums. Measure it with Multi-Test Strips or the API GH & KH Test Kit Combo. 2. KH is Carbonate hardness (KH). This measures the water’s buffering ability. KH is a measure of the water’s ability to withstand rapid changes in pH. This can pose a danger to fish. Like GH, it is measured in dKH (degrees of KH) or ppm, and we recommend keeping it at 3 dKH (50 ppm) or above for most freshwater aquariums to prevent pH swings. It can be measured with Multi-Test Strips, or the API GH & H Test Kit Combo.
API-GH & H Test 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. The API Phosphate Test Kit can measure it.
API Phosphate Test Kit
1. Copper: The copper-containing medications used to treat fish diseases may contain copper. The API Copper Test Kit can be used to determine the level of copper in tap water and to prescribe the right amount of copper-based medicine for sick fish.
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
How and when to test aquarium water
Ideally, water should be tested as often as possible, but in the past, test kits were often time-consuming and cost prohibitive to use very often. Fish keepers might overlook something unusual in their tanks and not test the water. Therefore, we developed the Aquarium Co-Op test strips to be faster and cheaper to use so that you can test more frequently for peace of mind. These are some of the most common situations in which you should test your water.
1. New Aquarium When setting up a new fish tank, it takes a while to cycle the aquarium so that the biological filtration is mature enough to purify the water from your fish’s toxic waste. While the aquarium is cycling, it is important to frequently test the water on a daily basis to make sure the ammonia, nitrite, and nitrate levels do not get too high, so get the Ammonia Test Strips and Multi-Test Strips. If the results are consistently safe and repeatable, you can decrease testing to every three days, then once a week, and eventually once a month. You can read the full article about aquarium cycles.
1. Tank Maintenance Once your aquarium is cycled, you may only need to use the Multi-Test Strips every 2-4 weeks to check the nitrate level, which can become toxic at very high levels. We aim to maintain nitrate levels below 50 ppm. If the nitrate level is between 75 and 100 ppm, it’s time for a water change. Live plants are essential for aquariums. They help to reduce the amount of water changes needed by consuming nitrate. Follow our water chart flow chart to figure out how often to do water changes based on the nitrate reading.
1. Sick Fish If your animals are displaying signs of illness or some are missing from the tank, it’s time to check every parameter possible to help you diagnose the issue. 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 are used to measure the nitrate levels. It should be between 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. If you want to increase plant growth by adding CO2 gas, the Dennerle Co2 Quick Test will help you find out how much CO2 is present in the aquarium.
1. Outdoor Pond Large outdoor ponds that have large volumes of water should be tested at least three to five times per year with the Multi-Test Strips or Ammonia Test Strips. The water quality should be checked at the beginning of each season to determine how it has fared in the winter. You should check the water quality during the middle of the season, as the fish have been eating different food. Also, the pond will evaporate faster in warmer weather.
Before you start preparing for winter, ensure that all water parameters have been checked at the end of the pond season. 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. Take a look at them and get out there enjoying nature everyday!