# Is dechlorination of top-off water needed?



## tekkguy (Jan 3, 2013)

Yes, add decholorinator when you top off or you'll kill your bacteria. I never top off with less than 1 gallon at a time to my 5 gallon tank, and I dose 1ml of the dechlor to go with it (mine calls for 1ml per gallon). I've seen others say to always dose for the whole tank, but I haven't bothered. If it's a very small nano, and you're adding less than an easily measurable amount as a result, you might want to dose the whole thing (unless it's very very frequent).

Word of advice on the raw shrimp method, since I've done it several times before ... your ammonia is probably off the charts if you're seeing a bloom, and you should take the shrimp out now or you'll actually stall the cycle.


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## bluestems (Feb 7, 2012)

I keep a container of de-chlorinated water that I use for small daily top-offs.


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## pwolfe (Mar 2, 2011)

I keep a milk jug for my tanks top offs. I treat with prime and let it get to room temp before using it.


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## Couesfanatic (Sep 28, 2009)

You may kill a very small amount of bacteria, but not enough to notice anything. I did it for a while and had no effects. But you really should be topping off with RO water. Your water hardness will go up if you top off with tap, unless you are keeping on top of your water changes with ro or some form. 

That water that evaporates out is pure, so should the water going back in.


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## Cinbos (Dec 8, 2012)

Good thread, always thought about this. I heard letting water sit out for 24 hours without dosing dechlorinator is also fine. I haven't done this myself, but does anyone know if there is any truth to that?


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## tekkguy (Jan 3, 2013)

Cinbos said:


> Good thread, always thought about this. I heard letting water sit out for 24 hours without dosing dechlorinator is also fine. I haven't done this myself, but does anyone know if there is any truth to that?


If your water department uses chlorine, it's fine. If they use chloramine (as more of them are now), it doesn't matter how long the water sits out. You need a product. Why take the risk?


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## Cinbos (Dec 8, 2012)

tekkguy said:


> If your water department uses chlorine, it's fine. If they use chloramine (as more of them are now), it doesn't matter how long the water sits out. You need a product. Why take the risk?


Answers my question, thanks!


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## ryguy76 (Nov 8, 2011)

Great info. Thanks. 



> Word of advice on the raw shrimp method, since I've done it several times before ... your ammonia is probably off the charts if you're seeing a bloom, and you should take the shrimp out now or you'll actually stall the cycle.


I've just taken the shrimp out... I was getting 8ppm on an API test every second day and no nitrites, so I'm glad you mentioned this.

I suppose I should dose with some fish food up to 1ppm once the ammonia starts going down? I don't see the point of adding more shrimp in if the ammonia amount given off from a half shrimp is so much.

As for using RO water, our city water is very low on TDS, so I didn't think using RO was necessary.


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## maxwellag (Mar 30, 2012)

Cinbos said:


> Good thread, always thought about this. I heard letting water sit out for 24 hours without dosing dechlorinator is also fine. I haven't done this myself, but does anyone know if there is any truth to that?


The chlorine will gas off when you do this, but the heavy metals in most tap water don't gas off. These heavy metals are harmful to fish/shrimp, which is one of the reasons why Prime is a necessity.


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## ryguy76 (Nov 8, 2011)

I just did a 50% WC and the ammonia level is between 4 and 8 ppm. probably closer to 4. 

Should I be ok with it there?


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