Why You NEED Water Conditioner For Aquariums (And Other FAQ’s)

Last Updated on 2023-07-04

If you’re wondering why adding water conditioner to your fish tank is so important, then you’ve come to the right article. In this article, not only will you learn what water conditioner is, but you’ll also learn what it does, how much you need, what happens when you don’t use it, and much much more!

So keep reading to find out everything you need to know!

What Is Water Conditioner?

First of all, water conditioner is a chemical that gets added to tap water to remove chlorine. It often contains sodium thiosulfate, which reduces chlorine to chloride, which is harmless to fish.

What Does Water Conditioner Do For Your Aquarium?

Water conditioner is vital for aquariums because it neutralizes the chlorine and chloramine in the water, which are extremely toxic and dangerous to fish. In fact, if left untreated, they can kill your fish rapidly.

On top of this, they also neutralize unwanted heavy metals in the aquarium as well, which can build up over time in your fish’s body, causing an early death.

When Should You Add Water Conditioner To Your Aquarium?

You should add a water conditioner to your aquarium everytime you perform a water change. It’s generally recommended to perform a water change every week or two, depending on the size of the tank and the amount of water used. 

How Much Water Conditioner Should You Use Per Gallon?

While each brand of water conditioner will have its own recommendations on how much you should use, a general rule of thumb is to use 1ml per gallon of water.

But of course, some brands will need more, and some will need less!

How Much Water Conditioner Is Too Much?

Fortunately, it’s actually incredibly hard to overdose a tank with water conditioner. Short of pouring half the bottle into your tank, the chances of too much being added are slim.

If you feel like you’ve added too much to the tank, you can perform a water change, as well as using an airstone to aerate your tank and keep it well-oxygenated.

How Long Does Conditioner Take To Work?

Water conditioner takes around 2-5 minutes to neutralize the chemicals in your tank. However, if you have a larger tank, then you’ll need to make sure it’s getting circulated around. 

If the water conditioner doesn’t circulate around the tank, then it may take up to 30 minutes to neutralize all of the chemicals.

What Is The Best Water Conditioner To Use?

Most name-brand water conditioners are going to be fine for your tank; however, the water conditioner I’d recommend is API Stress Coat. Not only is API Stress Coat a water conditioner, but it also contains aloe vera, which helps reduce stress in fish as well as heal any injuries!

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Here are some more frequently asked questions that people have about adding water conditioners to their tanks.

How Much Water Conditioner For A 5, 10, or 20 Gallon Tank?

Generally, about 5ml of water conditioner will be needed in a 5-gallon tank, 10ml of water conditioner in a 10-gallon tank, and 20ml of water conditioner in a 20-gallon tank. With an extra 1ml per gallon every time you perform a water change.

How Long After Using Water Conditioner Can You Add Fish?

It is generally recommended to add fish to the tank 15 minutes after you’ve added water conditioner. However, if you do have a tank with poor circulation, then you should wait longer to make sure all the chemicals in the tank have been neutralized.

Can You Add Water Conditioner While Fish Are In The Tank?

It’s perfectly fine to add water conditioner to a tank with fish already in it, as long as you’re only removing a small amount of water, to begin with. If you’re performing a complete water change, then you should keep your fish in water that has already been treated for 15 minutes before adding them back to the main tank.

Does Letting Water Sit Remove Chlorine?

If you let water sit, then the chlorine will generally dissipate within 24 hours. However, it can take up to 5 days, depending on the amount of chlorine in your tap water originally as well as other factors.


As you can see, a water conditioner is one of the most important tools in any fish keeper’s arsenal, so if you haven’t started using it, you should begin to do so immediately!

And if you liked this article, make sure you check out the rest of the website! Otherwise, have a great day!

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Hey! I'm Nicolas from Iguane Media !

Blogger and Owner of the betta care fish guide
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