The “conditioner,” also called a “dechlorinator” for fish systems, eliminates chlorine from the water to make it safe for fish. Some also work with the more stable chemical chloramine, which is produced by combining ammonia and chlorine. No matter what product to use, always abide by the directions. Even if it’s difficult to overdose, there is no need to squander it.

Pond dechlorinator filter cartridges that can be attached to water hoses are readily available in the marketplace, making them especially appropriate for the routine filling of ponds and aquariums. By doing this, the tap water is treated in a way suitable with biotopes, and most chlorine and heavy metals would be bound during filling.

Why is dechlorination recommended for fish systems?

Chlorine is toxic to fish. It damages their gills severely and causes asphyxiation and death. Most city water systems employ chlorine or chloramine to make water safe for human consumption. Having proper water management or even using bottled water can prevent chlorine poisoning. Be reminded though that some bottled water lacks the minerals and buffers that fish need to survive.

Chlorine poisoning in fish has no proven cure. If chlorine is found in fish tanks, the fish would probably die. Therefore, the fish tank water should always be checked and treated.

Most cities do not regularly add chlorine or chloramine to their water supplies. They wait until coliform bacteria reach a specific level just before they treat it with chlorine to destroy these organisms. Despite never adding dechlorinator nor experiencing issues, it does not imply that the fish are unharmed. Pond dechlorinator filters can always be a safe choice.

How does the dechlorinator function?

The sodium thiosulfate (H10Na2O8S2) found in many dechlorinators (pond dechlorinator filters) interacts with chlorine (Cl2) to create hydrogen chloride (2HCl), sulphur (S), and sodium sulphate (Na2SO4). Chloride is safe for the environment and does not affect fish.

Chloramine dechlorinators

Chloramine water treatment removes only chlorine, leaving ammonia behind. Typically, you don’t need to be concerned with the slight ammonia blip if the tank water is cycled properly and is not frequently changed massively. However, some treatments go a step further and treat chlorine and ammonia.

In this common product, sodium hydroxymethanesulfonate is the active component (HOCH2SO3–). (Other brands might employ various substances.) It produces water and aminomethanesulfonate (H2NCH2SO3-) when linked to ammonia (NH3) (H2O). Chlorine can interact with the sulfonate end to form the safe compound chloride.

Bubbling the chlorine off?

If you are certain that chlorine is being used to treat the water, this can be done. Since chlorine is volatile, adding aeration for roughly 24 hours will cause the chlorine to “bubble off” and make the water safe for fish. Bubble all you want, but if the water has been chloramine-treated instead, the chloramine won’t disappear.

Natural method of getting rid of chlorine and chloramine

If adding chemicals to the tank doesn’t sit well with the fish owner, they can use an activated carbon or KDF filter to eliminate the chlorine and chloramine. As the carbon depletes, there is a need to replace the filter or carbon frequently.

When to add dechlorinator?

Add the dechlorinator to a small bucket of water 5–10 minutes before transferring the water to the tank.

It is advised to add the first half of the dose at the midway point and the second half at the finish if you are pouring several gallons through a hose without a carbon filter to avoid overdosing.