How to Make Tap Water Safe for Fish Without Conditioner?

how to make tap water safe for fish without conditioner

We’ll discuss what’s in tap water, what to worry about, and more. Then, we’ll examine techniques for preparing tap water for aquarium use without the use of a water conditioner.

It would seem obvious to fill tanks with tap water. Unfortunately, it contains dangerous substances like chlorine and chloramine that can sicken fish. To make tap water safe, you must therefore treat it.

You can make tap water safe for your fish in a variety of ways, though. Tap water can be made safe for your fish by using a reverse osmosis system, applying UV light, or even vitamin C treatment. As a result of the extreme nature of these techniques, you can also boil tap water to make it safe for fish or simply let the water sit for a day or two.

How to Make Tap Water Safe for Fish Without Conditioner?

I am aware of how trying and perplexing getting an aquarium for the first time can be. I can understand how stressful it must be to worry about every little detail.

Everybody who is just starting out experiences the same thing. Don’t worry about it; they are likely to make a few common mistakes made by beginners. But don’t worry; I’m here to assist.

You must test your tap water to determine its condition before taking any steps to make it safe. Since there isn’t a single, universal method for purifying tap water, you can choose the best approach once you know which chemicals are present in the water. When testing, measure the following things:

  • pH balanced
  • Calcium carbonate (kH)
  • General water hardness (gH)
  • Iron
  • Copper
  • Lead
  • Mercury
  • Arsenic

Keep in mind that chloramine, which is more difficult to remove than chlorine, may require some level of chemical treatment in tap water. To learn how to dechlorinate water for fish and make it safe, use one of these methods:

how to make tap water safe for fish without conditioner

Leave the Water to Sit

Allowing tap water to naturally aerate itself is the simplest way to make it fish-safe without adding any chemical additives or conditioners. To remove chlorine, you must let the water sit undisturbed for at least 24 hours.

If you really don’t want to mess up the chemical makeup of your tank water, you have to leave it out in the open for around 24 hours. The length of time the water must be left out in the open and unattended depends on how much or how much chlorine is present in it.

It is better to wait a little longer than to take a chance. Once the water has been left alone for a while, the chlorine will naturally evaporate. Sincere to say, this is the least expensive way to make your tap water fish-safe. Aside from the requested time, there won’t be any additional costs.

But a different strategy is also required when addressing tap water that also contains chloramine. Because chloramine isn’t air soluble, it will stay in the tap water as a residue even if you let it sit for a longer period of time.

But after sitting for at least 24 hours, the chlorine in the water will simply evaporate into the air. When you leave the water in the sun and a big container, the evaporation will take less than or almost 20 hours.

Chlorine will be more difficult to dissolve in the air in a smaller container and in the absence of sunlight.

Boil the Water

You can boil tap water to get rid of chloramine if your tank also contains chlorine. Chloramine cannot be removed by letting water sit for at least 12 hours, as we have already mentioned. That’s because it doesn’t vaporize quickly or easily.

However, in order for this method to be effective, you must boil at least 10 gallons of water for an hour in order to eliminate 1 milligram per liter.

The majority of city water has at least 2 milligrams per liter, and some of it has as much as 4 milligrams. It shouldn’t be more than this, though, as consuming more than this would be dangerous for people.

Boiling water to remove chlorine is therefore a cumbersome process. Despite the fact that you could allow enough time for the chloramine to dissipate from the water, this approach is not recommended for use with large fish tanks.

Air Pump

By agitating the water’s surface, air pumps aerate the water, increasing the amount of oxygen in it. While letting your tap water sit, you can use an air pump to hasten the dechlorination process.

how to make tap water safe for fish without conditioner

As more oxygen enters the tank during aeration, chlorine, and carbon dioxide leaves. Because this process takes place at the water’s surface, air pumps create water bubbles that rise to the top and burst, releasing the surface tension.

Aeration is less effective in deep tanks with small surfaces. But for wide, shallow tanks with a lot of surface area, it’s a great way to get rid of chlorine.

Do not forget that air pumping will not remove chloramine from the tank. You’d require a chemical solution for that.

Air Stone

Similar to air pumps, air stones or aquarium bubblers enhance the water circulation in the tank. They only produce tiny bubbles, so they work better in smaller tanks. Aquatic aeration is improved by smaller bubbles.

The procedure is the same other than that. As they ascend to the water’s surface, the bubbles take out the carbon and chlorine while adding more oxygen.

Reverse Osmosis Unit (RO)

A reverse osmosis (RO) filtration system is the most efficient way to purify tap water.

Using a network of specialized filter chambers, RO filter systems process tap water. Reverse osmosis filter systems remove:

  • Chlorine
  • Chloramine
  • Heavy metals
  • Nutrients like phosphate and nitrate
  • Salts and minerals.

RO water can be blended with conditioned tap water to create just about any hardness and pH level.

Your tank will remain cleaner and require less maintenance because it is devoid of nutrients that encourage the growth of algae.

Water Filter System

Installing a water filter system is a practical way to make tap water fish-safe. This means that every time you turn on the faucet, the system will get rid of the dangerous chemicals, leaving the water safe to use in your aquarium.

how to make tap water safe for fish without conditioner

Once more, using this technique might deprive fish of some necessary nutrients. But to fix this, simply test the water with a remineralizing solution to see what minerals need to be added.

Ultraviolet Light Lamp

An increasingly common dechlorination method is UV light. Chlorine and chloramine compounds are converted into detachable byproducts by ultraviolet systems that employ high-intensity, broad-spectrum light. This operates between 140 and 400 nm in wavelength.

The advantage of UV disinfection lamps is that they don’t need any conditioners or chemicals to function. Additionally, they can clean the water, get rid of algae, stop diseases, and improve the environment for fish.

Vitamin C Treatment

Let’s now revisit another home remedy. Have you considered adding lemon or vinegar to the tank? To be completely honest, I’ve always been curious about feeding fish lemon (don’t do this; it will change the pH). of the tank, trust me I have tried this).

Vitamin C can actually be used to remove both chlorine and chloramine. However, consuming lemon or any other acidic food will not be effective. You must get ascorbic acid that is made specifically for use in fish tanks. However, avoid pouring this into the fish tank.

For each gallon of tap water, you intend to use, add a teaspoon of ascorbic acid. Always check the pH. of water before pouring it into the tank.

Can You Fill Your Tank With Tap Water?

Yes, you can fill your aquarium with tap water, but only after removing the chlorine. Typically, your fish shouldn’t drink tap water. Because of the chlorine in it, your fish may experience serious health issues or even pass away.

Before filling your aquarium, it is essential to make sure the tap water is fish-safe. But why exactly should it be made fish-safe?

Why Should You Make Tap Water Safe for Fish?

For good reason, tap water has chlorine in it. When treating water, particularly public water, chlorine is a common disinfectant used. In order to lower the risk of water-borne illnesses and make the water safe for human consumption, chlorine effectively destroys viruses and bacteria in public water.

As a result, chlorine is very likely to be present in public water supplies. You should make tap water fish-safe for the following reasons.

how to make tap water safe for fish without conditioner

What’s in My Tap Water?

Calcium, magnesium, sulfates, and carbonates are just a few of the minerals found in tap water, whether it comes from a well or a water treatment facility. These minerals don’t harm aquatic life and are safe to use.

Along with nitrate and iron, the nutrients phosphate and silicate may also be present in your water.


Fish suffer terrible consequences from chlorine. Acute necrosis, which results in cell death and is dangerous, is brought on by chlorine toxicity. This is because the chlorine in the tank reacts with organic material and living tissue, leading to respiratory issues and, in the worst scenarios, asphyxiation.

According to Reviews in Fisheries Science, stress brought on by the shifting weather conditions also has an impact on fish, in addition to chlorine.

The amount of chlorine present in the water determines how quickly they perish. The severity of the effects on smaller fish is more likely to be greater than on larger fish, but depending on the chlorine levels in the tank, all fish can succumb to the toxicity within hours. Signs that your fish are dying from a chlorine-related condition include:

  • Pale, mucus-covered scales
  • Redness on various parts of their body
  • Gasping for air at the water’s surface
  • Erratic swimming
  • Loss of appetite
  • Stress

Inexperienced owners who don’t treat their tap water before adding it to their tank frequently end up with acute necrosis.

Although mostly safe for humans, chlorine is fatal to fish. Because of this, inexperienced owners are blind to the risks posed by chlorine. Between 0.5 and 2.0 parts per million (ppm), chlorine is present in the water in varying amounts.


Chloramine is a substance that is used to clean and disinfect water to keep people healthy. As a combination of chlorine and ammonia, it is regarded as being more dangerous than chlorine. Additionally, it persists in tap water for a longer period of time than chlorine and is less likely to degrade.

Chloramine is poisonous to fish because it enters their bloodstream through their gills. Fish, therefore, have a difficult time properly absorbing oxygen and gasp at the surface. They might exhibit other symptoms that resemble chlorine poisonings, such as stress, erratic swimming, and redness around their gills.

how to make tap water safe for fish without conditioner

Between 0.002 ppm and 0.005 ppm is the safe range for chloramine. Fish cannot survive at any elevation. You can buy a testing kit from most aquatic stores to determine the precise concentrations if you think your tank contains chloramine. To keep your fish from perishing, though, you’ll have to act quickly.

Incorrect PH Levels

There are specific pH requirements for every tank. Regarding aquariums, a pH of 7.0 is regarded as neutral. The ideal pH range for your fish tank will largely depend on the species you have, but most tropical aquariums thrive at a pH of 6.8 to 7.6. These fish need the following pH levels:

  • Angelfish: 6.0 to 7.0
  • Clown loach: 6.0 to 6.5
  • Goldfish: 7.0 to 7.5
  • Harlequin rasbora: 6.0 to 6.5
  • Hatchetfish: 6.0 to 7.0
  • Neon tetra: 5.8 to 6.2
  • Plecostomus: 5.0 to 7.0
  • Silver dollar: 6.0 to 7.0
  • Tiger barb: 6.0 to 6.5
  • Zebra danio: 6.5 to 7.0

Fish can get sick when you fill their aquariums with tap water with an unfavorable pH level. Some fish, like discus and other cichlids, have very little tolerance for pH levels outside of their ideal range, and they won’t survive very long in unsuitable water.

Furthermore, toxic chemicals like ammonia rise when the pH of the water suddenly changes. Given how quickly it poisons fish, this chemical is among the deadliest tanks encountered. As a result, they’ll develop the following symptoms:

  • Lethargy
  • Loss of appetite
  • Red or cloudy eyes
  • Gasping at the water’s surface
  • Redness around gills
  • Death

To avoid this, you must be careful when adding tap water to your tank at a time and carefully monitor the pH. You’ll need to take action to change the pH of the water if necessary so that your fish can thrive.

Heavy Metals

Occasionally, tap water contains heavy metals. Heavy metals tend to be more toxic in hard water, as researchers at the Department of Environmental Sciences have found. Tap water contains the following metals:


Iron is toxic at concentrations between 0.1 and 10 parts per million (ppm), and it is deadly at even lower levels. Depending on the pH of the water, it also reacts differently. If pH levels are 7.0 or above, iron hydroxides appear on fish gills, causing:

  • Suffocation
  • Gill tissue swelling
  • Mucous secretion

Chronic copper exposure harms the spleen, kidneys, and gills. The immune system will also be impacted, making it more susceptible to illnesses.

how to make tap water safe for fish without conditioner

Algae growth is energized by iron and this can lead to a variety of issues. This includes elevated ammonia levels and a harmful algae bloom. Without even mentioning how quickly algae overruns the entire tank and is unsightly.

Owners must first filter out the metal because iron levels rise with aeration.


Copper can enter your fish tank through your tap water if your plumbing is made of copper. Copper sulfate can kill living things and is frequently used to treat fish parasites that cause illnesses like ich.

Copper, regrettably, is another poisonous substance. Because of this, when the water is treated with copper, you must quarantine fish in a different tank. Your fish could become ill if it gets into the tank. Copper kills all manner of things, including:

  • Anemones
  • Crabs
  • Filter bacteria
  • Live corals
  • Live rock
  • Shrimps

Conditions will worsen and eventually harm your fish if copper is allowed to kill the tank’s beneficial bacteria in particular. The good news is that a heavy metal remover can quickly remove copper from the tank.


In large concentrations, zinc is regarded as one of the heavy metals that are most toxic to fish. By destroying the gill tissues, it accomplishes this. Stress, which is also brought on by it, frequently causes death.

According to The University of Chicago Press Journals, a fish’s resistance to zinc poisoning depends on its species. Similarly, zinc toxicity is affected by these factors:

  • The hardness of the diluted water
  • The dissolved oxygen concentration
  • The water’s temperature
  • The fish’s ability to acclimatize
  • Age

Zinc enters the aquarium’s water through tainted tap water, just like other heavy metals.

Is Tap Water Bad for Your Fish?

how to make tap water safe for fish without conditioner

I can’t guarantee that tap water is safe for your fish or that it’s bad, so I guess it depends.

To be completely honest, whether tap water is suitable for your fish depends on its chlorine content and a few other water-related factors. When using tap water for your fish, chlorine is typically the main bad guy. Make sure to take the necessary precautions if you really want to use tap water in the tank.

Until and unless it contains a high level or even a slight hint of chlorine, tap water is bad for your fish.

Otherwise, tap water is your lifesaver if a test for chlorine, chloramine, and other harmful impurities yields a zero reading. Choosing what water to use in the fish tank is the simplest and least expensive option.

But always test anything you use first. And be sure to take the necessary action if you discover any chlorine or other impurities.

Final Thoughts

If you carefully follow my instructions, you will perform exceptionally well. Making tap water safe for your fish is possible in a variety of ways. Simply pick the option that is more convenient for you and effective.

You should test the water with the appropriate test kits after eliminating the chlorine from the tap water with one of the above-mentioned sure methods to make sure your aquarium fish are no longer harmed. Depending on the type of fish you want to keep, you can test for additional water characteristics like nitrate levels, general hardness, and other issues.

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