# Water changes and Chlorine



## Brando (Oct 6, 2010)

getting close to starting an 80 gallon, ordering stuff but coming up with some questions in advance.
This occurred to me today:
I intend to follow a regime of water changes, i know to try to get the water as close to the correct temp as possible when adding it to the tank, but i was curious...if the cycle has stabilized and all bacteria are good in the filter system, wont adding fresh chlorinated water destroy those bacterial colonies?

do i just add a de-chlorinating product to the existing tank water or is the added amount of "fresh" insignificant enough to affect anything?
( did i mention im new at this?)


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## rtbob (Jul 18, 2010)

You must add something to remove the chlorine. I use Seachem Prime. It is highly concentrated, 1ml treats 10 gallons. It also detoxifies ammonia and nitrites which might be in your tap water and it removes heavy metals.

Either treat the water in a bucket as your filling the bucket or if you use a python type system figure out how much water your going to add to the tank and treat the tank before adding the water.

Some people will let their change water sit in a bucket for 24 hours before adding to the tank. This will effectively allow the chlorine to evaporate from the tap water. I don't think it would have any effect on the ammonia/nitrites/metals (if they are present) however.

I would also recommend highly a test kit. I use API Master test kit. Testing the water is the only way you will know if your tank has completed the cycle. Once your tank has cycled it is a very good idea to test the nitrate level and keep it below 40ppm by doing water changes. If your fish start showing any kind of symptoms one of the first things you should do is test all the water parameters to insure they are with in safe levels to rule the water out as a cause of the symptoms. It is also a good idea to test your tap water so you have a baseline for it.

Do not get the test strips as they are inaccurate when compared to the liquid test kit.

Good luck with your new tank!


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## jrman83 (Jul 9, 2010)

I use Prime also.

Chlorine will kill your bacteria. Just remember this when rinsing filter media - where much of your beneficial bacteria is. Use your tank water or treated tap water to do this.


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## Martini2108 (Jul 23, 2010)

Chlorine is very bad for tank, always de-chlorinate water before putting in the tank or while.


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## chris oe (Feb 27, 2009)

If you add dechlorinator to the bucket you should be fine, most say you can use the water immediately. Often I add with the first bucket all I'm going to need and then I just fill the tank, and I haven't had a problem with my biofilter yet (been doing this since the 70's) better to let a tiny bit of chlorine get by for a small amount of time than to skip those partial water changes.


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## Brando (Oct 6, 2010)

Thanks, i have the seachem in my order.


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## susankat (Nov 15, 2008)

I use a python and prime as my conditioner. I basically treat with enough for the entire tank then just run the water from the tap.


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## mfgann (Oct 21, 2010)

You can either treat the whole tank, and add water from the tap, or treat each bucket. I usually treat each bucket. 

There are those that let the buckets sit out so the chlorine evaporates, but chloramine will not evaporate over the 24 hour period. The dechlorinators take care of this and a few other nasty things that can show up in tapwater I think. Just try to aim for the same temp as the tank also, so the fish don't geta huge temp spike.

Good luck!


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## sivakv (Aug 6, 2010)

Apart from chlorine, chloramine is used in tap water, unlike chlorine, chloramine(chlorine+ammonia) does not evaporate, chloramine is used specifically for this property. Might need to be treated.


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## Brando (Oct 6, 2010)

susankat said:


> I use a python and prime as my conditioner. I basically treat with enough for the entire tank then just run the water from the tap.


Here is my thought...
take out 25% of the water
treat the whole tank
turn off filter
refill and mix
allow to set for a short time
turn filter back on.

Logic: While the filter is off, untreated water is not circulating through it, therefore protecting it and the bacteria from chlorine within until untreated water is "treated" in the tank.
when you tun the filter back on enough time should have elapsed for the new water to be "safe" for the filter.


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## jrman83 (Jul 9, 2010)

If you put conditioner in the tank first, just put enough for the water that you're putting back in. If you put it in the tank first, the conditioner will react to the new water coming into the tank as it enters. You can turn the filter off if you like, but it is not necessary.


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## chris oe (Feb 27, 2009)

It is important to know if your water utility uses chlorine or chloramine or a combination. Fortunately you can get that information either by calling or checking their website, sometimes they'll send you more information about other water parameters that are neat to have, like hardness and other things they test and treat for. 

In addition to getting the info your local water company can give, periodically check the stats of the water coming out of your tap to get a baseline, so you know what your water change water is generally like, since water changes won't get you above what your change water base line is.


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## beaslbob (May 29, 2009)

Brando said:


> getting close to starting an 80 gallon, ordering stuff but coming up with some questions in advance.
> This occurred to me today:
> I intend to follow a regime of water changes, i know to try to get the water as close to the correct temp as possible when adding it to the tank, but i was curious...if the cycle has stabilized and all bacteria are good in the filter system, wont adding fresh chlorinated water destroy those bacterial colonies?
> 
> ...


I just replace water that evaporates in my highly planted tanks. works fine with no chemicals added.

But that could be different with large water changes.


my .02


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## Brando (Oct 6, 2010)

chris oe said:


> It is important to know if your water utility uses chlorine or chloramine or a combination. Fortunately you can get that information either by calling or checking their website, sometimes they'll send you more information about other water parameters that are neat to have, like hardness and other things they test and treat for.
> 
> In addition to getting the info your local water company can give, periodically check the stats of the water coming out of your tap to get a baseline, so you know what your water change water is generally like, since water changes won't get you above what your change water base line is.


According to my towns water quality report, listed under "disinfectants" is only this: 
MRDL MRDLG Units Average/Detection Level Range
Chlorine 4 4 ppm 1.3 / 0.24 - 2.50


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