Maintaining a healthy aquarium isn’t just about feeding your fish and keeping the tank clean - it all starts with the water. The quality of your tank's water will directly impact the quality of life for your aquatic friends, and poor conditions can lead to stress, disease and in the worst case scenario, death.
This makes regular water testing essential. To help ensure you’re creating a happy and healthy environment for your fish friends, in this blog, we’re going to break down the basics of how to test your fish tank water, including what to check for and how to treat these issues.
Why do you need to test your fish tank water?
Whether you have a new or an established aquarium, having clean, balanced water for your fish is just as important as it is for us to have clean air to breathe. If chemicals like ammonia get out of hand or bacteria grow beyond a safe level, then your fish may face illness and/or death.
Luckily, there are many easy and efficient ways you can test your aquarium water and once you know how, it’s simple to figure out what you need to ensure your tank is balanced.
How to test fish tank water
Water issues can be wide-ranging and can affect your tank in various ways. Luckily, with the amount of aquarium test strips and kits readily available today, testing your aquarium water has never been easier. A chemical reagent is mixed with a sample of aquarium water and changes colour based on the water parameter being measured. Below are the most common parameters you should be testing for and the effect they can have on your tank.
1. Ammonia
High ammonia levels can be very toxic to your aquatics and can cause serious harm. Ammonia is usually produced by your fish and invertebrates as it comes from their waste. Ammonia should stay at 0 ppm (parts per million).
You can measure this with ammonia test strips for a quick and simple way to monitor ammonia levels in aquarium water. These strips are suitable for both coldwater and tropical setups and will help detect harmful ammonia build-up before it affects fish health.
If you find your ammonia levels are too low or too high, we recommend doing a full or partial water change immediately and adding an ammonia neutralising agent such as the Seachem Prime Water Conditioner and testing again to ensure balanced levels.
Aquarium Ammonia 6, Strip Water Test Kit - £10.99
Seachem Prime Water Conditioner - £8.99
2. Nitrate
Elevated nitrate levels can cause unwanted algae growth, and although they’re not particularly toxic to fish like substances such as ammonia, they can still cause stress and stunt the growth of your fish. We recommend keeping nitrate at 50 ppm or below. If you keep live plants in your aquarium, they consume nitrate as food, so you should aim to keep nitrate levels at a minimum of 20 ppm to keep your plants healthy.
You can measure your nitrate levels with these nitrate test strips, and if you’re finding your tank's levels are too high or too low, a simple water change with clean water is the most effective solution.
Waterlife Nitrate Water Test NO3 - £8.49
3. Nitrite
Not to be confused with nitrate, nitrite is a toxic substance for aquatic life as it replaces the oxygen in their blood and can lead to “brown blood disease” as well as burning their gills and skin. Nitrite levels should be kept at 0 ppm.
You can test your nitrite levels using nitrite test strips for peace of mind. However, if you find that your nitrite levels are too high, then a healthy biological filter is essential for removing nitrite. In severe cases, you can also perform emergency water changes for quick results.
Waterlife Nitrite NO2 Water Test - £6.99
4. Chlorine
While chlorine is added to tap water to eliminate pathogens, it's harmful to fish and must be neutralised to ensure their well-being. This is why you shouldn’t use untreated tap water to top up your aquarium water. Chlorine should be at 0 ppm, and you can test that this is the case with these quick test strips that will let you know the levels of a variety of chemicals, including your chlorine levels, for peace of mind.
If you find your chlorine levels too high, then we suggest using a chlorine neutraliser, but you can also let the water age for 24 hours to allow natural dissipation. However, the latter isn’t as effective or efficient as using chlorine solutions.
Dymax Water Quick Test 7 In 1 Dip Test - £13.75
5. pH
pH refers to water acidity and alkalinity levels. However, the suitable pH levels for your tank will differ depending on the type of tank you have. For example:
Freshwater fish - need between 6.5 to 8.0 pH levels in order to thrive.
Tropical fish - are a bit more fussy and need between 6.8 to 7.8 for a happy home.
Marine fish - The pH for a marine tank should be between 8.1 and 8.4
However, it’s also good to check what your specific fish requires to ensure you’re providing the best environment possible. For the best all-in-one solution, try this API pH Test & Adjuster Kit, which provides a practical solution for monitoring and adjusting pH levels in all types of aquariums.
API pH Test & Adjuster Kit - £12.50
6. Hardness
There are two types of hardness levels kH and gH. kH refers to the carbonate hardness, and the higher the kH the less likely the pH will rapidly change - which is unsafe for your fish. We recommend keeping the kH at about 50ppm or above for freshwater aquariums.
gH is the general hardness of the water and is the measure of dissolved calcium and magnesium in the water. These minerals are essential for healthy animal and plant growth and we recommend between 70 - 140 ppm. If hardness is too low you can raise it with a calcium or magnesium salt by using this Salifert Calcium, KH & Magnesium Test Kit Bundle, if it’s too high you can reduce it by conducting a water change using soft water.
Salifert Calcium, KH & Magnesium Test Kit Bundle - £34.95
How to test for different aquariums?
Depending on what type of tank you have, whether fresh or saltwater, the levels in which you need to keep your tank balanced will change, which can make it hard to know what you need to test for.
Luckily, for any beginners out there who need a bit of extra help, there are many test kits that will provide you with everything you need, from test strips to solutions so you can enjoy full peace of mind that you’re creating a suitable environment for your aquatics.
For freshwater aquariums this JBL Pro Aqua Test Freshwater Test Kit is a professional kit that ensures you have everything you need for freshwater tank testing including iron, oxygen, pH levels and much more - giving beginners all the right tools for creating a suitable freshwater environment.
JBL Pro Aqua Test Freshwater Test Kit - £87.93
For saltwater aquariums keep on top of testing with the API Saltwater Master Test Kit, made to prepare first time fish owners with everything they need for looking after a saltwater aquarium. Complete with fast acting pH, Ammonia, Nitrite, and Nitrate tests.
API Saltwater Master Test Kit - £27.75
How often should to test your aquarium water
Ideally, your aquarium's water will be tested as often as possible, but the amount you’ll need to test your tank's water will depend on circumstances.
A new aquarium - When dealing with a new aquarium, you’ll need to cycle it first, which we have more information on in our blog on how to cycle a fish tank. While the aquarium is cycling, you’ll need to test the water on a daily basis to make sure the ammonia, nitrite, and nitrate levels do not get too high.
Tank maintenance - Once your aquarium is cycled and your fish are settled into their new home, you can test your aquarium water every 3-4 weeks to ensure all levels are still balanced and within a healthy range.
A tank with sick fish - If your aquatics are displaying signs of illness, you should check your water immediately for every parameter. Start by checking the water temperature, followed by the ammonia levels, pH levels, etc. The key is to not only determine if the measurements are within a healthy range but also to evaluate if they differ greatly from the usual values you have seen in the past.
Signs your tank's water quality is poor
Sometimes you may notice poor water quality before you even test for it. Knowing what to look for in your tank's water is essential for tackling issues before they cause serious harm. Luckily, poor water quality can often be identified by a few different things such as:
- Cloudy or discoloured water
- Bad smells coming from your aquarium
- Algae growth
- Sick or stressed fish (this can look like lethargy, loss of appetite, gasping at the water surface)
Get everything you need for a balanced aquarium with Aquacadabra
No matter whether you’re setting up or maintaining a tank, regularly testing your fish tank water is one of the most important steps you can take to ensure a healthy and stable environment for your aquatic pets.
Discover our range of aquarium test kits to help you catch potential issues early and take corrective action before they become serious problems, or discover aquarium treatments for fast-acting solutions to treat unbalanced water.