# When do you add dechlorinator during water change



## Method (Feb 13, 2011)

What type of dechlorinator do you use? I generally use SeaChem products (Prime at home, Safe at school). In my opinion you're more likely to dechlorinate your water successfully in small batches BEFORE adding it to your tank. Otherwise it may take a while for the dechlorinator to find and bind to your chlorine or chloramine. 

I'm not sure that dechlorinator kills good bacteria. Maybe someone else has a better insight for this particular question.


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## moonwasaloon (May 24, 2011)

Im sorry, im talking about the chlorine killing the good bacteria


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## Method (Feb 13, 2011)

In that case I think you're probably right. Sequester the chlorine before it ever has a chance to get near your biofilter.


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## Hoppy (Dec 24, 2005)

I always start the flow of new water to the tank, then immediately add enough Prime to treat the whole tank volume of water. I learned to do it this way from the experts years ago, and as far as I know, most experienced planted tank keepers do it this way. And, as I recall, this is how Seachem recommends using Prime.


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## sohankpatel (Jul 10, 2015)

I use an aqueon water changer, and i just add enough to treat the entire tank slowly as I fill.


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## roostertech (Oct 27, 2015)

A lot of people (youtube videos) do this sequence:
* remove old water, 
* add Prime directly to tank dosed at full tank volume, 
* refill water back up.

I personally want a bit of extra safety so my sequence:
* Fill a container with new tap water
* Add prime to the container
* Run a powerhead in there for about 30mins
* Remove old water
* Drip new water in over 30mins


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## skelley (Jul 18, 2011)

I've always been a little uncertain about this as well, because of the wording on several bottles of dechlorinator. Many say that they work immediately, not continuing over the course of 20 min (or however long it takes to do your WC). In reading that, my understanding is that chlorinated water added after the "immediate" dechlorination may not be completely, if at all, treated. Is my reading of this too literal? Perhaps not all dechlorinators work the same way?


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## stingrayness (Feb 14, 2016)

For the past decade I've always just put enough prime into the bucket of new water to treat the bucket of new water I put in the tank. I usually have the prime in the bucket for at most a minute before putting the water in my tank. I've never had a problem with this method


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## Hoppy (Dec 24, 2005)

stingrayness said:


> For the past decade I've always just put enough prime into the bucket of new water to treat the bucket of new water I put in the tank. I usually have the prime in the bucket for at most a minute before putting the water in my tank. I've never had a problem with this method


I know many people do it this way too. This should demonstrate that the timing of adding the Prime isn't critical, since there are multiple techniques for adding it.


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## stingrayness (Feb 14, 2016)

I've actually never heard of anyone dosing the full tank with prime before adding freshwater! That seems so sketchy to me lol but its probably more convenient on much larger tanks. The biggest tank I had was 60 gallons and I just used a big bucket lol


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