How To Remove Tannins From Aquarium Water – 7 Tested Tips

Knowing how to remove tannins from aquarium water is a useful and effective way to protect your fish and clean your tank. Tannins are one of the chemicals like nitrates, ammonia, and phenols that contain toxic substances in your fish.

It sounds familiar, yet many novices don’t get the know-how. So this article will give you simple methods with a complete guide for discarding tannins from aquarium water for a good fish tank. Let’s scroll down for further information.

What Are Tannins?

Tannins, also known as tannic acid, are a water-soluble polyphenol compound abundant in natural plants.

The plant kingdom includes an abundant source of tannins. They will seep into the aquarium and change into brown or yellow when they exist in the driftwood.

Tannins can paint the aquarium yellowish or brownish. Discoloration of water doesn’t harm the fish, so it is not a serious problem. Yet, tannins can gradually lower the PH of the water because of their acidity, which impairs fish and makes your tank polluted.

Except for South American fish, most fish can die in an acidic environment if the water tank has tannins.

Tannins can paint the aquarium yellowish or brownish

How To Remove Tannins From Aquarium Water

Distilled Water

Filling your tank with distilled water and tap water is the first simple method you can try. You may use this way to soften the hard water in equal amounts.

Distilled water decomposes the toxic chemicals and compounds present in your tank, thereby reducing the tannin level.

Boiling The Driftwood

Boiling driftwood is the fastest and easiest way to get rid of tannins. You can notice the improvement within a few days because they can not withstand high temperatures and develop on dead trees.

Besides, you can discard tannins from your tank by processing driftwood with an electric stove or a kitchen stove.

Adding Rain Water to Your Aquarium

Surprisingly, rainwater is good to help you reduce the tannins in your aquarium quickly.

Collecting and monitoring rainwater for an aquarium is a haunting task. Thus, you should care about the requirements below to collect rainwater in your tank successfully.

Build plumbing or indoor sewer lines that are not metal with clear paths to allow the water to flow easily in germ-free areas.

Keep your rainwater source in a fresh place without air pollution since these harmful particles can pollute your aquarium.

Let your rainwater sit within a few minutes before picking it up so that all the dirt or other toxic particles can deposit at the bottom, increasing aquarium water’s quality.

increasing aquarium water’s quality

Ion Exchange

A common method that helps soften the hard water is using ion exchange. Luckily, it also removes tannins from tank water and facilitates the growth of aquarium plants.

In theory, ion exchange will activate the reaction among ions, in which negatively charged tannin ions will be replaced with other anions but with different chemical properties.

The complete anionic resin treatment gives twofold benefits to aquarium water. It can remove the number of tannins but doesn’t lower the mineral nutrients necessary for your fish to survive.

So, you can try this method to reduce tannins in your aquarium water and supply a peaceful and fresh environment for your fish to live and grow.

Use Carbon

Activated charcoal is also useful to clean tannins in your tank. Use a proper amount and pour it into your aquarium filter.

Although this technique can consume more effort and time, removing tannins from your tank is effective and quick.

One teaspoon of activated carbon is suitable for one gallon of tank water for the best result.

Use A Reverse Osmosis Filter

Another way to remove some tannins in your fish tank is to install a reverse osmosis filter on your faucet.

Molecules can diffuse across a semipermeable membrane in traditional osmosis. The process varies to allow the pure water molecules to go through the membrane.

All additive compounds in tap water, including tannins, can be filtered out, so the water is clear and soft after that.

Adding Baking Soda

Baking soda is a great substance that can help remove dirt or detox harmful chemicals. In the same vein, it is effective in reducing the tannins in your aquarium.

Every 5 gallons of water calls for a tablespoon of baking soda to clean your aquarium quickly. Yet, baking soda also affects the pH of the water in your tank and makes the fish suffer from a pH shock.

Do your research about the pH level your fish need to survive in water before adding baking soda because different fish species ask for different parameters in their environment. They also thrive at variable levels of tannins.

Note: When you reduce the tannins amount by using baking soda, you must remove your fish from the aquarium water.


How Long Does It Take For Tannins To Go Away?

The time often depends on the decoration or wood material you use for your aquarium. Normally, this process will take a few days or weeks. However, most tannins will have gone away within ten days.

Will Tannins harm Fish?

Yes, tannins can harm your fish. However, don’t worry; you can use some useful methods such as ion exchange, using carbon, and adding baking soda to remove them from your water.

What Is The Fastest Way To Remove Tannins From Driftwood?

Boiling driftwood is the fastest way to remove tannins from them. Boiling disinfects the driftwood, killing fungal spores or algae that may have survived in the aquarium with driftwood.


The above is a full guide with simple methods to help you know how to remove tannins from aquarium water. Despite the benefits of tannins in the tank, their acidic component can harm your fish. They will hinder the growth of fish and the natural plants in the aquarium environment.

Thus, with the detailed instructions in this article, you should choose the best way to remove this toxic chemical from your tank.

However, whichever method you pick and use, pay attention to the PH of your aquarium environment to prevent your fish from sudden shocks when dropping in acidity or alkalinity.