Water Conditioner: 11 Things You Should Know (For Beginners)

A water conditioner is a type of solvent used in treating different types of aquarium water. Since aquarists have different sources of aquarium water, most of these would contain chemicals that are toxic to fish.

To prevent endangering your tank inhabitants, a water conditioner would be the solution to neutralize the chemicals in your tank water.

Can Fish Live Without A Water Conditioner?

Yes, fish can live without a water conditioner, so long as the aquarium water they live in is free from heavy metals and toxic chemicals such as chlorine and chloramine. There are alternatives in dechlorinating water as well and this deems it safe for fish to live in tanks without a water conditioner.

Truthfully, it’s not a matter of using a water conditioner or not because the safety of fish, and other tank inhabitants, would largely depend on the safeness of the aquarium water being used.

It’s a fact that not every person gets their water from the same source. Some cities use water that has a considerable amount of chemicals in them as well as heavy metals. Then some cities have softer waters, which are far safer to use for fish by the way (but not for fishes that need to live in hardy water conditions).

For instance, in the U.S., there are 118 out of 120 locations that went over the recommended amount of lead. Take note that this would cause serious health problems to humans, but what more if people use this for their fish? The answer is clear—fish would either get injured or die.

Moreover, not every aquarist swears by using water conditioners. Some recommend using water conditioners since it helps with neutralizing chlorine, chloramine, and other heavy metals.

On the other hand, there are also a few fish keepers who would stray away from using water conditioners in the first place because it’s composed of inorganic compounds (e.g. sodium thiosulfate and EDTA tetrasodium salt). While these inorganic compounds may not pose any threat to fish, still, it’s enough to keep other aquarists away from it because it’s inorganic.

Luckily, there are other methods you can do that don’t require inorganic components. These methods are also a bit complicated at first but they do make promising results. We’ll talk more about this in the following section of the article.

What Can I Use If I Don’t Have A Water Conditioner?

You can opt for reverse osmosis, electromagnetic water treatment, electronic water condition, and template-assisted crystallization if you don’t have a water conditioner.

The most common method to use out of all methods listed above would be reverse osmosis. So what exactly is reverse osmosis and what does it do?

Reverse Osmosis

A reverse osmosis system is responsible for producing pure water that’s safe for all sorts of tank inhabitants. It eliminates toxic chemicals, impurities, heavy metals, pesticides, and arsenic (a metallic chemical found in groundwater).

Reverse osmosis works by letting water pass through a semi-permeable membrane, and what this does is it’s able to only let small molecules pass through, so all the toxic impurities from tap water (or whatever source of water that you’ve put inside your tank) won’t make its way to the tank itself and harm its inhabitants.

Moreover, reverse osmosis systems work great for different kinds of tanks. For instance, a freshwater tank would benefit from reverse osmosis because this system would provide water that’s free from general hardness and carbonate hardness.

So if you own species of fish that need soft waters, like a Discus fish for example, then an RO system would be perfect in place of a water conditioner.

Reverse osmosis also works well with marine and reef aquariums. An RO system would remove harmful elements such as phosphate, silicates, and nitrates to keep corals and fish safe. With the removal of these harmful chemicals, the growth of algae would also be prevented.

When it comes to maintenance, ensure that you will check on these RO systems regularly. This is to ensure that the system is always providing your tank with nothing but pure water.

Changing the filters in reverse osmosis systems would depend on its manufacturer instructions. Also, if there’s discoloration in your filters and the water pressure of your unit has dropped, that would be a clear sign to replace it (filter). As for the membrane, it would depend on manufacturer instructions on when to replace them.

Best Water Type For Your Aquarium

Reverse osmosis water and deionized water would be the best types of water you can use for your aquarium. These are considered the safest types of water because they can filter out contaminants well compared to other types of water (e.g. tap water and well water).

There are a lot of water sources people can choose from for their tanks and this can be a bit daunting at first, given the fact that you have to think about the pros and cons for each water source.

To keep this sweet and short, water sources like municipal tap water, well water, bottled water, and rainwater aren’t that good and here’s why:

  • Municipal tap water. Depending on the location, the contaminants present in the tap water would vary. Several tap waters have heavy metals in them, then in another location, tap water may have high levels of ammonia and asbestos (both of which are extremely harmful to fish).
  • Well water. Well water is usually located in agricultural sites, so despite not having any chlorine in well water, there will be other contaminants in it such as pesticides, solvents, nitrates and coliform (from fertilizer), so on and so forth.
  • Bottled water. These may be safe for human consumption, however, the process of making bottled water removes several beneficial minerals in it.

Also, there’s some bottled water that still contains a dangerous amount of chlorine. Lastly, purchasing a bunch of bottled water for your tank would be extremely costly, so this isn’t the best source of water for an aquarium.

  • Rainwater. This source of water would have few beneficial minerals in it and it may be contaminated by air pollutants too. Also, if the rainwater falls on the roof first before you get the chance to collect them, then there’s a high possibility the rainwater would have asbestos.

The best choice would be deionized water and reverse osmosis water because they’re mostly free of contaminants. If you would opt to use either of the two water sources, then you must have to remineralize it. This step is essential since both water sources tend to strip away even the beneficial minerals.

Choosing a water source that offers the best quality and purity would prevent the usage of a water conditioner because it won’t be necessary anymore since it won’t remove any chlorine and chloramine from an already purified and contaminant-free water.

Can You Overdose Aquarium Water Conditioner?

Yes, you can overdose an aquarium with a water conditioner, however, the safety margin is somewhat high and overdosing doesn’t put your fish’s life in danger.

There have been several aquarists that claim their fish stayed perfectly healthy despite overdosing their tanks using a water conditioner.

That would make sense since the purpose of a water conditioner is only to remove harmful contaminants in a tank, so once it has done its job, there won’t be anything else left for it to do to a tank.

However, if you’re still concerned for your fish and don’t want to take any risks with overdosing on a water conditioner, then it’s best to just follow the dosage recommendation shown in the water conditioner you’re using. This would guarantee the safety of your tank inhabitants as well as assure you, the owner.

Another solution to address your worry about overdosing with a water conditioner would be to change your water source to a pure one (deionized water or reverse osmosis water) so that you won’t have to rely on a water conditioner to take out harmful contaminants in it.

How Long Does A Water Conditioner Need To Sit Before Adding Fish?

You should let a water conditioner sit for 15 minutes before adding fish to the tank. For larger tanks, you should let the water conditioner sit for 30 minutes.

The 15-minute duration of letting the water conditioner sit inside the tank is merely an estimate, however, this is a recommended time frame from most aquarists. Water conditioners work quite fast and this beats leaving tap water to sit out and aerate (without the help coming from a water conditioner).

If you’re only going to let tap water aerate on its own and without the help from a water conditioner, that would roughly take less than 24 hours to dechlorinate. However, with the time frame given, it won’t effectively strip away every ounce of chlorine in the tap water.

If you’re aiming to get rid of all the chlorine in your tank, then you should let the tap water aerate for five days. Of course, other factors would also determine how long your tank would completely dechlorinate. Some examples would be the chlorine concentration of the tap water and the volume of the water itself.

Using a water conditioner would be of help to aquarists who want to dechlorinate their tanks faster and more efficiently. If you want to speed up the process even more, you can make use of water pumps, and this would help in circulating the water conditioner solvent in every corner of the tank.

Is Tap Water & Water Conditioner Safe For Plants?

Yes, tap water can be safe for plants if you do the proper steps in dechlorinating the water. Since tap water contains chlorine, you should dechlorinate it by using the following: leave the water out in the sun for 48 hours, use activated carbon, or use a water conditioner.

Do take note that plants in gardens and plants in aquariums (also referred to as hydroponics) are two different things and their tolerance for chlorine also differs.

Garden plants would have a much higher tolerance to chlorine compared to hydroponics, so it’s recommended that the tap water you’re using for your plants be dechlorinated first before putting in the plants inside the tank.

But first, you have to find out the level of chemicals (chlorine and chloramine) and PPM in your tap water. Once you’ve got the information for these, you’ll know what treatments are needed for your tank.

Refer to this short guide so you’ll know what to do with your tap water:

  • If your tap water has chlorine in it, get the volume of water you need for your tank, leave it out under the sun for 48 hours so that the chlorine would evaporate.
  • If your tap water has chloramine in it, you can also leave the volume of water you’re going to use under the sun. However, this process would take a long time to finish, instead, you can go for activated carbon. Activated carbon can help filter tap water and remove unwanted contaminants.
  • High levels of PPM can be addressed by using regular water filters. The downside of using such filters would be

Is Fish Water Conditioner Safe For Snakes?

Yes, a fish water conditioner is safe for snakes. There are also some brands of fish water conditioners that specifically indicate that their product is safe for amphibians and reptiles.

Since both a fish water conditioner and a reptile and amphibian water conditioner have the same function, which is to remove chlorine from tap water, both can be used interchangeably. So whether you own a reptile such as a snake, an amphibian, or a fish, you can use either of the two water conditioners for them.

It’s important to note that both the fish water conditioner and the reptile water conditioner vary in ingredients. Despite their differences in chemical content (a.k.a. ingredients), both can be used for either fish or reptiles.

However, veterinarians strongly recommend using reptile conditioner for tanks that have both snakes and fish in them, as for fish-only tanks, they recommend using a fish water conditioner instead.

A great water conditioner that’s suitable for fish, reptiles, and amphibians would be the TetraFauna AquaSafe Water Conditioner.

Do Aquarium Water Conditioners Expire?

Yes, aquarium water conditioners do expire. There are some brands of aquarium water conditioners that don’t indicate an expiry date, however, one mustn’t think that that means that it doesn’t expire. It’s best to contact the manufacturer of the product that you bought to know its expiration date.

Aquarium water conditioners like API Water Conditioner have expiry dates, specifically, these products tend to expire one to two years from the date of manufacture.

It’s always best to use an aquarium water conditioner before it expires because this is where the product is most effective. If people will still use their expired aquarium water conditioners, then the efficacy wouldn’t be the same as it was before it expired.

Moreover, there’s a difference when it comes to an aquarium water conditioner’s expiry when it’s been opened compared to when it’s completely sealed. A water conditioner that’s been opened should be used within 12 months, on the other hand, a sealed water conditioner can last from one to two years.

Granted that the sealed water conditioner isn’t exposed to sunlight and is kept at the appropriate room temperature, then it would last from one to two years, possibly even three years as well.

Are Water Conditioners And Stress Coats The Same?

Water conditioners and stress coats are two different things. A water conditioner conditions tap water by removing chlorine, chloramine, nitrate, and ammonia. Stress coats on the other hand condition tap water and reduces the stress of tank inhabitants.

With that being said, a water conditioner solely has one function which is to rid tap water from harmful elements such as chlorine, chloramine, nitrate, and ammonia. A water conditioner doesn’t have the stress-removing properties that a stress coat can provide.

Stress coats on the other hand can provide more than water conditioners. The former aquarium product has two main functions: first, it’s able to condition tap water by removing contaminants (chlorine, chloramine, nitrate, and ammonia), second, it’s able to reduce fish stress.

A lot of aquarists agree with the fact that a stress coat would be a better choice rather than relying on a water conditioner. It makes sense too since stress coats offer more benefits compared to a water conditioner.

Is Fluval Water Conditioner Good?

Yes, the Fluval water conditioner is good, however, it’s pricey.

The Fluval water conditioner isn’t merely a product that conditions tap water. Despite being identified as a water conditioner product, it acts more like a stress coat. As we’ve established previously, stress coats remove chlorine, chloramine, and harsh metals in tap water while reducing fish stress. It also helps fish heal faster from wounds that they’ve sustained from other fish or due to the condition of the tank (e.g. bacterial onslaughts).

The Fluval water conditioner can do everything a stress coat can and that makes it a great aquarium product to have. Moreover, Fluval is a well-known name for aquarists, so you know that you can rely on their products to be 100% useful, safe, and effective.


  • The Fluval water conditioner comes from a well-known brand called Hagen. That confirms its efficacy and quality.
  • It performs similarly to a stress coat; it not only conditions tap water but also it helps fish recover from their wounds a lot quicker. Moreover, it also protects the scales of fish.
  • It comes with several sizes: 2 Litres, 500mL, 250mL, and 120mL bottles. The variety of bottle sizes would give a person flexibility with their choice and choose which would best suit their needs.
  • The dilution ratio of the Fluval water conditioner beats other brands because you would only need a few drops for the product to take effect. Contrary to the Fluval water conditioner, other brands would require more doses to work efficiently.


  • The Fluval water conditioner is a bit on the pricey side, so you should be prepared for this one. While there may be other alternatives to this product, that would entirely be up for you to decide which product to buy.

Water Conditioner

Seachem Prime Fresh and Saltwater Conditioner, API Tap Water Conditioner, and Aqueon Tap Water Conditioner would be some of the best water conditioners in the market.

While there may be a lot of water conditioners to choose from, the products mentioned above are some of the best ones out there in the market. Also, these products have been part of a lot of aquarist’s arsenals just because of how reliable they are.

You can check out the reviews on Amazon for each of these water conditioners and see how they fare (according to the reviews of fellow aquarists).

Check them out here:

Seachem Prime Fresh and Saltwater Conditioner

API Tap Water Conditioner

Aqueon Tap Water Conditioner




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