Without a good test kit, it will be hard to determine the water quality of your fish tank. However, in this article, we will show you some methods on how to test your fish tank water without a kit.

You can take a sample of your water to the local store for testing or test fish tank water for pH without an aquarium test kit by making a pH indicator using distilled water and fresh red cabbage.

The essential water parameters to test for include nitrite & nitrate, ammonia, and pH. Read on to know more.

Ways to Test Fish Tank Water Without a Kit

Ammonia Nitrite Testing

If you can’t get test kits or take your water sample to the local fish store, you can observe your fish and study their behavior. This is an effective way to determine if there’s a decline in the water quality of your fish tank. Watch out for their appearance, and observe if there’s a smell coming from your fish tank’s water.

Observe your fish behavior for the following indicators:

  • Strained breathing
  • Yawning
  • Resting at the bottom of the fish tank more than usual
  • Less efficiency in swimming
  • Red gills
  • Gasping near the surface of the aquarium water or your tank’s filter
  • Less appetite for fish food
  • Discoloration

There are others, but the ones mentioned above are the major indicators to watch out for in your freshwater aquarium. These are common signs of high ammonia and nitrate levels in your water.

You can reduce the ammonia and nitrate levels by reducing the fish food you put in your aquarium. Fish feed harbors bacteria that break down the food particles, releasing ammonia in the process.

You can also take out dead fish that can possibly be the reason for the terrible smell you’re perceiving from your aquarium. Ensure there’s a regular water change. Ammonia is very toxic to fish and reducing it is necessary to keep your fish safe.

pH Testing

In the absence of test strips or a testing kit, you can determine the pH level of your tank’s water by using red cabbage and litmus paper. Using a test kit to determine your water pH is more reliable, but a litmus paper, will at the very least tell you if your water is neutral, alkaline, or acidic.

Litmus Paper

Get your blue and red litmus paper, then either insert it in water or drop water on its surface and wait for a color change. The tank water is alkaline if your blue litmus paper remains the same while your red litmus paper changes to blue. The tank water is acidic if the reverse is the case; the blue paper will change to red and the red paper will remain the same.

If there’s no change in color on either litmus paper, that means your tank water is neutral. This is a very convenient way of reading your water’s pH without a test kit.

Red Cabbage

You can use this vegetable to make pH test strips to determine the acidity of your water without a test kit. This vegetable contains a color molecule known as flavin, which makes it function similarly to a litmus paper or color chart in an aquarium water test of one of the essential water parameters.

To make the red cabbage indicator, carry out the following steps:

  • Cut the cabbage into small pieces and put them into a container. Boil tap water and pour it into the container. Leave it for about 10-15 minutes till you get a reddish-blue solution.
  • Pour about 100 ml of this testing solution into a 250 ml tube.
  • Add a few drops of your fish tank water to the solution, the color of the solution will change depending on the pH of your aquarium water supply.

If your water is red or purple, it’s very acidic. If your water is violet, it is acidic. If your water is alkaline, it will be bluish-green or blue. If your water is greenish-yellow, it means your water is very alkaline.

Observe the Nitrogen Cycle

It’s your job to ensure that your fish tank has a solid nitrogen cycle. New aquariums won’t have one in place yet, but you should notice it after a few water changes.

Change 25-30% of your tank’s water every day for a week, then switch it to weekly changes till you experience small cloudiness in your tank. Your cycle is in place the moment it clears.

Ensure your fish tank is empty before and during the process of building your nitrogen cycle. It can trigger stress which will either kill your fish or make it sick. So, we recommend establishing this cycle before adding fish.

How to Know If a Fish Tank Has Poor Water Quality?

The above-mentioned behavioral symptoms of fish which points to signs of high ammonia and nitrite levels are also one of the ways to determine if your water has poor quality without using a test kit. It’s a key thing to consider if you want to test fish tank water. Other ways include:

Green Water

Green water in your aquarium is mostly caused by algae growth. Algae is neither harmful to your fish nor other aquatic plants. On the contrary, they are beneficial, but they ruin the appearance of your tank. Algae, especially phytoplanktons reduce phosphates and nitrites levels.

They also oxygenate your water, consuming carbon dioxide in the process to keep the water’s pH in good shape. Owners of tanks add phytoplanktons to ensure their fish live healthier and longer.

In essence, phosphates and nitrates are responsible for the explosion of algae, resulting in green water. So to get rid of green water, you gave to eliminate phosphates and nitrates from your water.

Nitrate is a naturally-occurring element that originates from fish waste. Phosphates, on the other hand, originate from decomposing organic matter in tanks. The surest way to test the water for phosphate and nitrate levels is by either using a testing kit or taking your water sample to a local fish store.

To prevent increasing levels of phosphates and nitrites in your tank, avoid putting too many fish in your tank, overfeeding your fish, and invest in a filter that will reduce nitrates in your water. Also, avoid putting nitrate-feeding live rocks or live plants in your tank.

If the above-mentioned options are not effective, opt for chemical additives or water treatments designed to reduce nitrate and phosphate levels.

Cloudy Water

Cloudy water can be caused by bacterial blossom, gravel residue, dissolved minerals, and even the presence of algae in your tank. Similar to green water, it’s not harmful to fish and may clear on its own.

If the issue persists after 10 days, then that means the water has bad quality. You can solve this issue by using water conditioners. You can also use the reverse osmosis filter to remove solids and impurities from your water.

Last Advise

We advise that for a start, you should test the essential parameters twice or thrice every week. If you notice that over time, the essential parameters are stable, you can switch your testing frequency to once a month. Testing should be carried out especially when you notice certain signs or indications of a high concentration of nitrate.

Though you can still test fish tank water without a test kit, we recommend using an all-around aquarium water test kit for best results.

About the Author

Lucas Greer

Lucas vs. Wild - Lucas is a true nature lover and survivalist. When he's not teaching science at school, he can be found in nature, hiking, climbing, camping, and rafting. He knows all the tricks and DIYs for making unclean water drinkable with simple means in an emergency. At school, his students love him for his exciting water filtration projects.

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