Do We Need Water Conditioners? Which One to Choose

Do We Need Water Conditioners. Which One to Choose.

Tap water, which is a common source of water used in aquariums, contains disinfectants (chlorine/chloramine), heavy metals, and other impurities. These substances tend to pollute the water, making it unsafe for fish and other aquarium critters.

So, do aquarists need water conditioners? The answer is yes, since it is a cost-effective, quick, and sure-fire way to make impure tap water safe and habitable for aquarium pets.

Whether you are setting up a new aquarium or carrying out a partial water change, you need to make the tap water fit for use with a water conditioner.

Keep reading for everything you need to know about aquarium water conditioner, including how it works, types, good brands, Pros, Cons, and other useful information.

Recently I have come across a few articles describing different water conditioners. Unfortunately, the information in some of them was completely wrong. It even contradicted the description of the manufacturer!

Thus, I decided to do my own research and correct some of these falsehoods.

What is A Water Conditioner?

This is a formulation designed to be added to the tap water before using it in an aquarium. Water conditioner neutralizes chlorine and chloramine and detoxifies contaminants such as heavy metals that the tap water holds.

Chlorine and chloramine are employed by water treatment plants to treat tap water and make it safe for human consumption. These chemicals are majorly used for water disinfection since they can effectively kill bacteria and other microbes present in the water.

Unlike chloramine, chlorine is unstable and evaporates easily when tap water is left to sit for 24 hours or more. That said, allowing tap water to sit out for a day or more will not remove the chloramine content. And this necessitates the treatment of tap water with an aquarium water conditioner.

How Water Conditioner Works

Water conditioners contain an inorganic compound ‘sodium thiosulfate’ which reacts with the chlorine or chlorine portion of chloramine to form chloride ions which are harmless to aquarium fish and invertebrates.

Basically, the water conditioner forms ionic bonds that bind the chlorine molecules and gets rid of them in the process.

Some water conditioners also contain sulfonates which proceed to neutralize ammonia together with the chlorine present in the tap water. The water conditioner splits the chlorine & ammonia bond in the chloramine molecules and tackles both compounds separately.

To add to this, there are sophisticated products that come with Ethylene diamine tetra-acetic acid (EDTA) to bind and remove minerals and heavy metals.

Other known additives include Aloe vera, vitamins, and polyvinylpyrrolidones, a water-soluble polymer, to promote wound healing and improve the slime coats of your aquarium fish.

Why Do I Need A Water Conditioner?

The importance of water conditioners cannot be overstated. These specially formulated products are needed to make the tap water safe for use in the aquarium.

From the earlier discussion, it can be noted that tap water is typically unsafe for aquarium fish, frogs, and invertebrates (such as shrimp, freshwater crabs, crayfish, etc.), since it contains chlorine and chloramine which can be lethal to them.

These chemicals can cause harm to the gills or skin of your aquarium pets, thus hampering on their ability to absorb oxygen from the aquarium water.

The primary purpose of water conditioners is the detoxification of heavy metals and neutralization of chlorine and chloramine in the tap water, and hence making it safe for fish and other aquarium inhabitants.

Other benefits that may result from the addition of water conditioner to the aquarium water include reduction of stress level and/or preservation of the natural protective coating of aquarium fish.

How Often Should I Use A Water Conditioner?

Water conditioner should be used whenever you want to perform a water change in an established tank.

Whether you are disinfecting new live plants, or you need to replace/top up the aquarium water — do well to treat the container of tap water with a water conditioner.

Note: In my opinion, setting up a new tank is one of a few cases when you do not have to use a water conditioner. After all, nitrogen cycle takes a lot of time. At the same time, if you are going to cycle the tank with fish, you will still need it.

Other than that, you may also add a small dose of water conditioner to the tank water from time to time for additional benefits.

Can I Add Water Conditioner While The Fish or Shrimp Are In The Tank?

Yes, you can do that.

The best way to use water conditioner is to mix the tap water and water conditioner in a clean container and let it sit for at least 5 minutes before adding it to the tank.

This method ensures that the water conditioner dissolves evenly in the tap water before moving it to its final destination — the aquarium.

One may as well add water conditioner directly into the tank. However, it is not recommended and should be done only in case of an emergency. Why?

Because this practice poses a potential risk — which is the likelihood of your animals (especially fish) gulping the concentrated liquid before it is dissolved in the tank water.

So, to prevent this occurrence, for example, simply lure your aquarium fish to one side of the tank with fish food, then add water conditioner to the opposite side and stir the water briefly.

How Long Does Water Conditioner Take To Work?

Upon introduction, it takes about five minutes for the aquarium water conditioner to neutralize all the chlorine and chloramine content present in a container of tap water.

Keep in mind that dosage varies amongst brands.

Hence the outlined dosage for a particular product may not be the same as another. So be sure to follow the manufacturer’s instructions for the recommended dosage.

Types of Water Conditioners

  • Dechlorinators

This is the simplest form of water conditioner, and it contains sodium thiosulfate which deals with the chlorine content of the tap water.

Dechlorinators are very effective at eliminating chlorine. However, they cannot get rid of ammonia.

Thus, be sure to go for a chloramine neutralizer or complete water conditioner if you aim to tackle both chlorine and chloramine.

  • Chloramine Neutralisers

Chloramine neutralizers are formulations designed to eliminate chlorine, ammonia, and little traces of heavy metals.

They work by breaking down chloramine and neutralizing ammonia by either binding to the molecules of ammonia and rendering them harmless or converting toxic ammonia (NH3) to ammonium (NH4) which is non-toxic to aquarium pets.

  • Complete Water Conditioners

Complete water conditioners are the best option when it comes to the conditioning of tap water.

These products contain many active ingredients which effectively tackle chlorine, ammonia, and heavy metals including zinc, cadmium, lead, arsenic, and copper.

These sophisticated products also contain chemicals and extracts that help reduce stress and also restore/preserve the natural protective slime coats of fish in your aquarium.

Top 5 Aquarium Water Conditioners

Shopping for a water conditioner can be a bit tasking since there are lots of water conditioning products on the market. To ease this problem, we researched and put together a list of top 5 aquarium water conditioners, including a summary of their individual pros and cons.

The following products are among the best water conditioners for the hobby and as such, they can be used to treat tap water before use in a fish tank.

  • Seachem Prime

Seachem Prime. Do We Need Water Conditioners. Which One to Choose.Recognized as Seachem’s flagship product; Prime® is a complete and completed conditioner for both freshwater and saltwater aquariums.

Seachem Prime neutralizes chlorine and chloramine content of tap water and breakdowns toxic ammonia into a harmless form. It also detoxifies heavy metals, nitrites, and nitrates in the tank water (up to 48 hours) without impacting the pH.

Important: Detoxifies is not equal to removes. So, you may see what is called a “false positive” results when performing a test. That’s because technically all those chemicals are still there, they are just harmless for a time being.

Seachem Prime may be used during cycling to prevent ammonia/nitrite toxicity, or when topping off the tank or replacing aquarium water.

The product is available in different sizes: 50 ml, 100 ml, 250 ml, 500 ml, 1L, 2L, and 4L.

For dosage, use 1 capful (5 ml) for 50 gallons of water. Note that the cap is calibrated to allow for easy measurement. And each thread in the cap equals 1 ml, therefore 1 thread (1 ml) matches 10 gallons, and so forth.

A single 8 Fl Oz (236 ml) bottle can treat around 2350 US gallons (8700 liters) of tap water.

Seachem Prime
Pros Cons
Works almost instantly Has a strong sulphur odor
Excellent value for money  
High-concentrated formula  
Neutralizes chlorine and chloramine  
Detoxifies heavy metals, ammonia, nitrite, and nitrate  
Doesn’t alter the pH of the water  
Improves the fishes slime coats  
Safe for invertebrates (shrimp, crabs, crayfish, snails, etc.)  
Can be used in freshwater and saltwater tanks  
Skimmers will not over produce foam  

Seachem Prime – link to check the price on Amazon

  • Aqueon Water Conditioner

Aqueon Water Conditioner. Do We Need Water Conditioners. Which One to Choose.Aqueon water conditioner is an effective water conditioner that neutralizes chlorine and chloramine in tap water and also detoxifies heavy metals and ammonia.

This product promotes the natural regeneration of the slime coat of fish and it also helps in the healing process of wounded or sick fish.

Lastly, Aqueon water conditioner helps to reduce stress in aquarium fish during handling, transportation, or acclimation to a new environment.
Note: You are required to add 5 ml per 10 gallons (about 40 liters) of water.

A single 8 Fl Oz (236 ml) bottle can treat around 470 US gallons (1 740 liters) of tap water.

Aqueon water conditioner
Pros Cons
Neutralizes chlorine and chloramine Weak cap. It leaks easily
Detoxifies heavy metals and ammonia Makes water foam up
Promotes restoration of fish’s natural slime coat Low-concentrated formula, hence the product will reduce faster
Aids the healing of wounds For inverts (like shrimp) you need another product – Aqueon Shrimp Tank Plus
Reduces fish stress Too many negative feedbacks on fish dying after using the product
Safe for saltwater  tanks In saltwater tanks, it can remove only chlorine
Does not change the water’s PH  
Does not smell like Prime  

Aqueon water conditioner – link to check the price on Amazon

  • Tetra AquaSafe Plus

Tetra AquaSafe Plus. Do We Need Water Conditioners. Which One to Choose.Tetra AquaSafe Plus is a complete water conditioner with several active ingredients and extracts for improved efficiency.

This product is capable of neutralizing chlorine, chloramine, and heavy metals within few minutes. It contains seaweed extracts (natural biopolymers) which support the development of beneficial bacteria, plus powerful slime colloids to help protect the fish’s delicate gills and membranes.

Tetra AquaSafe Plus is formulated with essential vitamins and minerals to promote the health and vitality of your aquarium fish. You are required to use 5 ml per 10 gallons of water.

A single 8 Fl Oz (236 ml) bottle can treat around 470 US gallons (1 740 liters) of tap water.

Tetra AquaSafe Plus
Pros Cons
Detoxifies heavy metals and other impurities Incompatible with a protein skimmer
Neutralizes chlorine and chloramine                          May cause harm to invertebrates
Contains natural biopolymers and essential vitamins Does not detoxifies ammonia, nitrites, and nitrates
Encourages wound healing  
Reduces stress in fish  
Enhances the protective slime coat  
Will not alter the pH  
Safe for saltwater  tanks  
Smell is barely noticeable  
Works instantly  

Tetra AquaSafe Plus – link to check the price on Amazon

  • API Tap Water Conditioner

API Tap Water Conditioner. Do We Need Water Conditioners. Which One to Choose.API tap water conditioner dechlorinates and dechloraminates tap water, and detoxifies heavy metals present in the water.

API tap water conditioner is suitable for both freshwater and saltwater tanks. And the product offers a super-concentrated formula that allows you to treat high volumes of water with less water conditioner.

Direction: 1 ml per 20 gallons (about 80 liters) of water.

A single 8 Fl Oz (236 ml) bottle can treat around 4720 US gallons (around 17 500 liters) of tap water.

API tap water conditioner
Pros Cons
High-concentrated formula (probably the highest among all water conditioners) Overdosing can kill your fish, inverts, and plants!
Great for large tanks (excellent value for money) It smells bad
Removes chlorine and neutralizes chloramine Difficult to measure dosage for tanks below 20 gallons. Impossible to measure using the cap
Detoxifies heavy metals Need to buy a small eyedropper to measure
Can be used in freshwater and saltwater tanks Not compatible with a protein skimmer
Great for cycling tanks because it does not detoxifies ammonia and nitrites Does not detoxifies ammonia, nitrites, and nitrates
Safe for invertebrates (shrimp, crabs, crayfish, snails, etc.) if properly dosed  
Reduces fish stress  
Forms a synthetic slime coating on your fish  
Doesn’t affect pH of the water  

API tap water conditioner – link to check the price on Amazon

  • API Stress Coat

API Stress Coat. Do We Need Water Conditioners. Which One to Choose.Another water conditioner from API ® — API stress coat effectively removes chlorine, neutralizes chloramine, and detoxifies heavy metals found in the tap water.

API stress coat is the only water conditioner that contains Aloe Vera and is proven to reduce fish stress by 40%! The product supports the healing of wounds and damaged tissue, decreases stress and electrolyte loss, and reduces fish susceptibility to infections.

If you need to treat injured fins or a stress coat, this is for you.

It restores the natural protective slime coat, a property that the API water conditioner lacks. Basically, API stress coat is more focused on maintaining health of the fish in an established aquarium. Whereas API tap water conditioner is better for the initial setup of the tank.

Direction: Add 5 ml per 10 gallons of water.

A single 8 Fl Oz (236 ml) bottle can treat around 470 US gallons (around 1 740 liters) of tap water.

API stress coat
Pros Cons
Treats the water instantly Not compatible with a protein skimmer
Neutralizes chlorine and chloramine Does not detoxifies ammonia, nitrites, and nitrates
Detoxifies heavy metals (like copper, lead, etc.) Invertebrates don’t benefit from the product
Doesn’t affect the pH levels  
Compatible with fish, inverts, and plants  
Promotes healing of wounds and damaged tissue  
Reduces stress and electrolyte loss in fish  
It is shrimp safe  
Can be used in fresh or saltwater aquariums  
Does not smell  

API stress coat – link to check the price on Amazon

Water conditioners

Comparison Table (Main characteristics)

  Seachem Prime Aqueon Water Conditioner Tetra AquaSafe Plus API tap Water Conditioner API stress coat
(US Gallons/L)
8 Fl Oz
(236 ml) bottle
2350/8700 470/1740 470/1740 4720/17500 470/1740
Chlorine & chloramine


Yes Yes Yes Yes Yes
Detoxifies ammonia, nitrite, and nitrate


Yes No No No No
Detoxifies heavy metals


Yes Yes Yes Yes Yes


Yes No No Yes No
Slime coating


Yes Yes Yes Yes Yes!
Shrimp safe


Yes No Yes/No Yes Yes
pH changes


No No No No No
Safe for saltwater  


Yes No Yes Yes Yes


48 hours No data Yes 24 hours No data

In Conclusion

Treating tap water with a good water conditioner is a necessary course of action before adding it to your aquarium. A good water conditioner will neutralize harmful chlorine and chloramine, and detoxify heavy metals in the tap water, making it safe for your aquatic buddies.

If you need a complete water conditioner from a reputable manufacturer for your fish tank, I suggest you make a pick from the list of top 5 aquarium water conditioners.

In my opinion, Seachem Prime is the most suitable water conditioning product because it ticks virtually all the right boxes.

This product is a super-concentrated formulation and it contains a variety of essential ingredients including a slime coat booster (Even though it is not as effective as API stress coat).

Moreover, Seachem Prime is quite affordable and it offers outstanding value per gallon of water than most competing products in the market.

Prime ® will quickly neutralize chlorine, chloramine, and detoxify nitrogenous compounds and heavy metals without affecting the pH of your aquarium water. Apart from that, it will promote the natural regeneration of your fish’s slime coat, and reduce fish stress and susceptibility to microbial infections.

Lastly, water conditioners are must have for any fish or shrimp keeper, however, they are not meant to be considered a complete substitute for maintaining adequate filtration equipment or general maintenance.

One thought on “Do We Need Water Conditioners? Which One to Choose

  1. Sooo interesting read. You’re so knowledgable and experienced, but most importantly happy to share your knowledge with the lucky ones who will come across your articles. Big thank you.

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