# When to add dechlorinator



## Nont (1 Nov 2022)

Hello,

I’m new to using tap water. I would like to know to know if I should be dosing dechlorinator before or after adding water into the tank?


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## Hanuman (1 Nov 2022)

Preferably before.


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## Yugang (1 Nov 2022)

Is there any risk that commercial dechlorinators (I use Sera), interact with the fertilisers in the tank? 

This was on my list of suspects when I had some issues (timing correlated with change of declorinator) but it is not clear to me if there would be a scientific basis for  that.


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## Hanuman (1 Nov 2022)

Yugang said:


> Is there any risk that commercial dechlorinators (I use Sera), interact with the fertilisers in the tank?


Definitely. I can't tell you for sure the specifics for Sera but if you use Seachem Prime it will basically remove ammonia, nitrites and nitrates. However Seachem also says this:


> Prime® will bind up those compounds for up to 48 hours. If they are still present after that time frame, they are released back into the water, unless Prime® is re-dosed accordingly. Also, if your ammonia or nitrite levels are increasing within a 24-hour period, Prime® can be re-dosed every 48 hours.


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## Yugang (1 Nov 2022)

Any concern front dosing the week's macros at the same time of doing a water change and using dechlorinator?
I am now 'front' dosing the week's macros the morning after WC (Micros dosed daily), the downside obviously being an unwanted TDS swing.

@Nont I assume your question is answered, hope you don't feel I am hijacking your thread.


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## Hanuman (1 Nov 2022)

My opinion is that it's best to use filtered tap water (sediment + carbon and maybe an additional filter of your choice) rather than use chemical dechlorinators in planted tanks. You will save money and won't worry about the dechlorinator removing your ferts. I think some dechlorinators also remove some metals.

This said, years ago when doing WC I usually removed the water from the tank first, then added the dechlorinator and finally added fresh TAP water. Nothing died and plants were doing fine. In fact now that I am thinking, I believe many people do it that way for practical reasons.


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## Hufsa (1 Nov 2022)

For the fishes perspective it makes more sense and should be safer to add dechlorinator/water conditioner to the change water before it comes in contact with the fish.
If you have to dose the water conditioner into the tank itself then be sure to dose for the full tank volume, and I would let it circulate in the tank for a bit so that it is evenly distributed and "ready to deal with" anything coming in with the untreated water change water.



Hanuman said:


> I think some dechlorinators also remove some metals.


I believe they contain EDTA and thats how they "bind to harmful metals", but dont quote me on that


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## jaypeecee (1 Nov 2022)

Hufsa said:


> I believe they contain EDTA and thats how they "bind to harmful metals", but dont quote me on that


Hi @Hufsa & Everyone,

For more information on Water Conditioners, you may want to take a look at the following:






						Water conditioners - The Free Freshwater and Saltwater Aquarium Encyclopedia Anyone Can Edit - The Aquarium Wiki
					






					www.theaquariumwiki.com
				




I find the Aquarium Wiki to be a handy resource.

JPC


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## Hanuman (1 Nov 2022)

jaypeecee said:


> Water conditioners - The Free Freshwater and Saltwater Aquarium Encyclopedia Anyone Can Edit - The Aquarium Wiki
> 
> 
> 
> ...


Nice. Seems comprehensive.


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## John q (1 Nov 2022)

Yugang said:


> Any concern front dosing the week's macros at the same time of doing a water change and using dechlorinator?


No non whatsoever. On a practical level myself and numerous others front load on water change day, using dechlorinator, without any issues. I'd guess if this were a real problem it would be well known in the aquascaping world and not confined to the odd occasional repeated myth. 

Also worth pointing out that a lot of the mumbo-jumbo advertising speel used by SeaChem Et al is infact mumbo-jumbo, their products don't actually remove all the nasties they proclaim, at best they render them less harmful to livestock, but doesn't mean plants can't uptake them.


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## xZaiox (1 Nov 2022)

Nont said:


> I would like to know to know if I should be dosing dechlorinator before or after adding water into the tank?


As others have said, ideally before, but I've found no issues doing it at the same time. I use a python water changer, and I use a 5ml syringe to pull up the amount of Seachem's Prime that I need (I usually slightly overdose it out of chlorine paranoia ), and while the tank is slowly filling up I periodically inject a little bit right where the water is entering the tank.

I've had zero issues from doing it this way, and in-fact most of my fish come up to the python hose while it's filling the tank - it gives off a lot of bubbles and the fish seem to like it for some reason.


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## mort (1 Nov 2022)

I've always added it to the mixing buckets first before I bring them up to roughly the same temperature. The commercial systems I looked after were exactly the same except the water was mixed in a much bigger container first and then pumped in.
With fert dosing we just waited a couple of hours.


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## Parablennius (2 Nov 2022)

Yugang said:


> Any concern front dosing the week's macros at the same time of doing a water change and using dechlorinator?
> I am now 'front' dosing the week's macros the morning after WC (Micros dosed daily), the downside obviously being an unwanted TDS swing.
> 
> @Nont I assume your question is answered, hope you don't feel I am hijacking your thread.


I front dose weeks NPK into my change water + dechlorinator. No TDS swing. Matches tank water.


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## Polly (2 Dec 2022)

Hanuman said:


> My opinion is that it's best to use filtered tap water (sediment + carbon and maybe an additional filter of your choice) rather than use chemical dechlorinators in planted tanks. You will save money and won't worry about the dechlorinator removing your ferts. I think some dechlorinators also remove some metals.


This is all very well if you absolutely know that your water company .only.  doses the water with Chlorine.   It will evaporate out of water if a full bucket is left  with an aerator, although how long that takes depends on turnover and size of bucket. 

However in  the UK, some water companies use Chloramine (Ammonia+Chlorine) which is far more stable and does not evaporate out.    So you need to use something to remove the chemical.      Activated carbon can work if there is a long enough contact time, but how long is long enough ?    And how do you tell when to  change it?
PFK have been recording which areas have now switched to Chloramine so you might want to check with your area before you decide how to proceed.   

Unfortunately water companies don't tell consumers when they switch to Chloramine, which has lead to under-treatment of water going into our aquaria with inevitable results.


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## ian_m (5 Dec 2022)

Some one on another fish keepers forum lost nearly £700 of fish due to chloramine being added to his tap water due to "emergency dechlorination" from a burst mains water pipe. 

Normally he just carbon filtered the water into large water butts and aerated & warmed for 24 hours before performing water changes on his rather larger collection of tanks in his "fish house". Well the majority of his fish died pretty soon after water change, as clearly carbon and aeration don't work with chloramine.  When water was tested chloramine was present.  Complained to water company but said water complied with UK regulations.

So addition of Prime or other dechlorinator would have prevented this. I think he closed his "fish house" down after this humungous loss....


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## Hanuman (5 Dec 2022)

Not sure where I read this but aren't there 2 types of carbon filters? Ones that are used for chlorine others for chloramine.


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## Tim1343 (5 Dec 2022)

Hanuman said:


> Not sure where I read this but aren't there 2 types of carbon filters? Ones that are used for chlorine others for chloramine.


That’s correct you can get carbon filters that deal with both chlorine and chloramine.


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## dw1305 (5 Dec 2022)

Hi all,


Polly said:


> However in the UK, some water companies use Chloramine (Ammonia+Chlorine) which is far more stable and does not evaporate out. So you need to use something to remove the chemical.





ian_m said:


> Some one on another fish keepers forum lost nearly £700 of fish due to chloramine being added to his tap water due to "emergency dechlorination" from a burst mains water pipe.


That is <"always the worry"> for me.  It is partially why I <"use rainwater and small volume water changes">. It is back to <"risk management"> and trying to stay in the "_green bit_" on the matrix.

 Chloramine dosing may not be very likely, but should it happen its effects are likely to be severe. Same with using CO2 <CO2 Disaster>, it is a risk you can avoid and there are <"severe consequences"> if things go <"pear-shaped">*.






* for @Hufsa 

cheers Darrel


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## Polly (17 Dec 2022)

Yes. We're looking at rainwater collection for this reason.   Our local authority claim they don't use Chloramine, but public health trumps everything so I doubt they could promise they'd never use it.

I'm just not sure how to keep the rainwater tub free of mozzies.   Had a nasty shock when they developed in my Sarracenia water holders.    Soon stopped that with... cat litter !


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## mort (18 Dec 2022)

Polly said:


> I'm just not sure how to keep the rainwater tub free of mozzies.



We don't get them in our water butts because we have simple lids over them if they didn't come with one. I have seen people use insect mesh netting as well, which let's water pass through (and still stops all the leaves etc).
If it's indoors you don't want the mozzies then you can strain the water through a sieve (I have a brine shrimp sieve plus a few others for varying larger sizes, made by hobby) first or just make sure you have fish interested in the live food. I can add them directly to my tank and they are gone in minutes.


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## ian_m (3 Jan 2023)

dw1305 said:


> Chloramine dosing may not be very likely, but should it happen its effects are likely to be severe. Same with using CO2 <CO2 Disaster>, it is a risk you can avoid and there are <"severe consequences"> if things go <"pear-shaped">*.


Over Xmas we had no water to 3-4 days, starting 21st December.  We were in Andorra skiing, so missed all the fun and games. Many peeps had no water or low pressure water Xmas day, which would make Xmas meal interesting. Many pubs cancelled their Xmas do's and meals as well, great news (NOT) if you have travelled huge distances to be with family and find Hotel closed and pub Xmas meal cancelled.

Local fish keeper reported chloramine in water when water started coming back after 4 days, obviously they "shock dosed" the pipes. He was not bothered as just didn't didn't change any water.


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## AlecF (3 Jan 2023)

The fish-keeper still had to know not to change the water. It would be good if water companies were more aware of fish-keepers and there was a system of alerts that could be shared.


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## Oldguy (4 Jan 2023)

You do need to know your water supplier/source. In big conurbations this would be tricky, had a friend whose tap water was one of three blends that feed into his distribution point.
Any interruptions to supply or pressure (letter throught the door about water supply disruption), the I do not do water changes.
My local water is local and is chlorinated and the house plumbing is old fashioned: mains water in to kitchen and garden taps and WC's the rest to header tanks in the roof void. So the hot water from the tap is 'old' and the cold water is from rain water butts.
I add a little sodium thiosulphate and some magnesium sulphate to the water change make up water.
If you have a good sense of smell chlorinated water from a fast following tap, especially first thing in the morning, will smell of chlorine while chloroamine will smell like a swimming pool with lots of children in it. Chlorine + pee + sweat = Chloroamine and similar chemicals. (And people swim for health?)


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