How To Reduce Water Hardness In Aquarium?


If you have a fish tank, you probably know that water hardness is one of the most common problems. Hard water can cause some serious issues for your aquarium inhabitants and even shorten their lifespan.

So, how to reduce water hardness in aquarium? Some ways will help us reduce hard water in an aquarium. Let’s jump to this post right away to discover.

What Is Water Hardness?

Water hardness can be daunting to keep up with, but it’s important for your fish. Harder water has more dissolved minerals, which means that they need less care, leading to healthier inhabitants of the aquarium.

The higher the mineral concentration in aquarium water, the tougher the water is thought to be.

The following are the water hardness testing kits that are used to estimate the water hardness:

General Hardness (GH)

The concentration of absorbed magnesium and calcium in the aquarium water is determined by general hardness.

Carbonate Hardness (KH) or Alkalinity

The amount of bicarbonate and carbonate ions in tank water is determined by carbonate hardness.

Some of the most popular aquarium fish are from places with a variety in water hardness, but some only exist in one type. That’s why knowing your General Hardness is so essential.

Why Would You Need To Soften Aquarium Water?

Allow Soft Water Fish To Thrive, Rather Than Just Survive

Softening the water in your aquarium will make it easier for you and keep all other fish healthy. You might notice an increase in coloration or immune systems to fight off diseases or infections more effectively due to increased vitality from newfound healthiness.

Breeding Soft Water Fish

To produce breeding males, you need to provide slightly more acidic water with optimal temperature. You should also acclimate your fish before transferring it into another tank that has drastically different conditions for the breeder and baby boomers alike.

Prevent Hard Water Stains And Limescale Deposits

Cleaning your tank without having to worry about the damaging effects of hard water can be a blessing. Cleaning stains and build-up is much easier than you think, even for those that don’t want it done professionally.

To avoid the stress of having an aesthetically unpleasing tank, soften your aquarium water gradually to find a good balance that works for you, and these issues will go away.

How To Reduce Water Hardness In Aquarium

Making hard water soft is not difficult and can make a difference to the safety and comfort of your fish. Just remember that changing the hardness level in an active aquarium should be done gradually to not cause any problems for them.

Reverse Osmosis

Nowadays, one needs to drink enough water, but many people are wary of their tap water’s bad taste or mineral content. Fortunately, there exists an effective solution: Reverse Osmosis! This filtration system works without chemicals and can remove up to 99% dissolved particles while leaving pure, clean water behind. No more chlorinated tastes or deposits from hard sources that harm our bodies over time.

The RO water filter works by forcing the hard, mineralized substance in your home’s plumbing through a porous material at high pressure. Anything left behind leaves only to allow pure and drinkable H2O passage.

One of the most important things to remember about RO water is that it’s a slow process, so be sure to process batches at once. You may also need a regular tap or specialty salt combined with yourRO filtered water to get an aquarium PH balance just right for you.

Water Softening Pillows

The best way to keep your water soft and clean is with a water softener pillow. These handy little gadgets use ionized resins, which will reduce the general hardness of aquariums while also increasing sodium levels for better conductivity.

They can be used in both fresh or saltwater tanks but must not touch mineral spirits. Like a battery, the medium can be recharged by immersing it in saltwater.

Softening your water is an easy way to make it more appealing for fish. These pillows will reduce hardness, but they work best in small aquariums with less than 25 gallons of capacity and should be recharged at least once every four weeks if you want optimal results.

Rain Water

You may be surprised to learn that it’s possible, even in the most urban areas of our country, for potable water-capture systems and storage containers thanks to rainwater. This means you don’t have to worry about chemicals leaching into your well or river system.

For safety purposes, though – it is imperative if this will be serving solely as drinking sources. Please ensure all equipment used are sterile food-grade items to avoid contamination from potentially harmful substances found around homes.


Peat moss is a great way to soften the aquarium water. It works by binding calcium and magnesium ions.

Still, it will also release gallic and tannic acids into the aquifer, attacking bicarbonates in fishes’ environments, reducing their pH levels even further.

One disadvantage of utilizing peat is that it might make your liquid brown for a period. However,  this isn’t harmful and will go away after the tannins are released.


Driftwood functions similarly to peat in that it helps to lower GH and PH levels.

Buying driftwood from your local fish shop or online is the best way to ensure that you avoid buying any unwanted parasites and invasive species. You can still boil bought driftwood for it to be safe.

Still, this will also help remove dirt/sediment before planting, so there are no nasty surprises later on when plants grow out of place due to being wet with dirty water.

Driftwood might turn your aquarium brown. Make sure to soak the driftwood for a few weeks before putting it in, or else you could end up hurting fish with tannins released from the wood itself.

Driftwood is a great way to add natural beauty and character to your aquarium. We recommend adding driftwood once you’ve filled it with water inside of an inch up from the bottom for best results.

Hence, there’s room for its long pieces or branches, which can grow as they break off over time if left unattended.


The hardness of the water in your aquarium is important for fish health. Fish need to be able to produce calcium carbonate deposits on their scales, fins, and other parts of their body so they can grow properly. So, how to reduce water hardness in aquarium?

If you are struggling with the water hardness in your aquarium, don’t worry. Our tips above will help reduce the amount of calcium and magnesium ions in your tank to make it safer for fish and other aquatic life. Give them a try today!

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