# Small amounts of water OK without dechlorinator??



## urbach (Apr 16, 2009)

It's not Ok if you are asking me. If your water contain only chlorine, risky for certain fishes especially shrimp. But if water also contain Chloramine, that will wipe out your beneficial bacteria plus livestock. Unless you aged the water between 12 till 24hrs,is OK without dechlorinator.


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## zachawry (May 28, 2013)

OK, thanks. It's not worth even a small risk, so I'll just add some then.


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## PlantedRich (Jul 21, 2010)

Just so there is not the wrong impression left for others to read-- Chlorine will dissipate in pretty short time. But if you have chloramine, this will not work. One of the primary reasons for using chloramine is that much less can be used and it lasts longer. Often weeks. 

Step one might be to find what your water treatment in Japan has used. If chlorine, I might look at storing some water in an open container for topoffs. A bubbler to stir the water will help keep it fresh as well as disspate quicker.


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## mistergreen (Dec 9, 2006)

I do it most times. If I need to add a gallon or 2, I don't bother with dechlorination. I wouldn't do that if my tap has chloramine.


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## MarkM (Sep 16, 2012)

I prepare a 5 g bucket of tap water by adding prime, I use this as top off water and just keep it with a lid on it in the utility room.


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## gSTiTcH (Feb 21, 2013)

Really, you should be topping off with RO or distilled anyway. Adding tap will further increase the buildup of TDS, minerals, etc. Remember that when water evaporates, it doesn't take minerals, salts, and such with it.


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## mistergreen (Dec 9, 2006)

gSTiTcH said:


> Really, you should be topping off with RO or distilled anyway. Adding tap will further increase the buildup of TDS, minerals, etc. Remember that when water evaporates, it doesn't take minerals, salts, and such with it.


Not a problem if you do regular water changes and have plants.


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## DarkCobra (Jun 22, 2004)

urbach said:


> But if water also contain Chloramine, that will wipe out your beneficial bacteria plus livestock.





mistergreen said:


> I wouldn't do that if my tap has chloramine.


Odd comments.

My tapwater contains 1ppm ammonia in the form of chloramine. The proposed 2L top-off into 65G would be adding 1% of the tank volume. So ammonia ppm rise = 0.01ppm. A trifling amount that won't even register on a test kit. If you're keeping sensitive shrimp, chances are your pH is under 7.0, at which point ammonia is non-toxic anyway.

In the end it's just a light snack for the biofilter and plants, munch munch gone.

The amount of chlorine is also similarly small, having been diluted 100X. It reacts with the first organic material it touches, and is consumed in the process. Biofilm surface area exceeds fauna surface area greatly. If we assume it's by a factor of 100X, then 99% of the already-diluted chlorine is absorbed by biofilms, and only 1% by fauna.

To put that in a different perspective, it is the same effective chlorine dosage to fauna as if you'd put them in a clean (biofilm and bacteria free) bucket, with one gallon of clean and chlorine-free water, then added 1/16 tsp. of water straight from the tap. I'll place my money on the fish not dieing, anyone care to bet against me? 

Oh, the biofilms will be fine too. So much of them vs. so little chlorine, the effect is immeasurable. And since you're actually feeding them a bit of extra ammonia at the same time, they bounce back from the slight damage faster than they would with chlorine alone.

Even in undiluted tapwater, sometimes nitrifying bacteria with a little higher than average chlorine resistance manages to colonize the water pipes. It uses the ammonia as a food source to grow faster than the chlorine can kill it. And having stripped both components from the water, other dangerous bacteria can grow unfettered downstream. That's why water companies have superchlorination events.

So yes, if you're just doing a very small top-off, skipping the dechlor is fine. I often do, no problems.


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## ktownhero (Mar 21, 2011)

Topping off with some tap water is no big deal, I do it all of the time. If I feel like the volume is too much, I add a little prime to my tank after I have already added the water but most of the time I just let it go. 

Freshwater tanks, especially planted ones, are very forgiving about using tap water. If we were talking reef, that would be a whole different story.


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## lochaber (Jan 23, 2012)

Just to add on to what DarkCobra said; chlorine in the tap water is the same basic principle as adding iodine to river/lake water when camping, or using bleach in emergency/survival situations - any time you are treating water that has visible particles/cloudiness it's generally advised to use at least a double dose. - This is because all the suspended particles will exhaust the iodine/bleach, and some microbes might be unaffected.

Dumping a bit of tap water in your tank, and it will quickly disperse, and the chlorine/chloramine will likely get exhausted reacting with tannins and whatever else is suspended/disolved in the water before it even encounters any critters.


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## Diana (Jan 14, 2010)

Ditto the several people who are saying it is OK. 

I top off my tanks roughly once a week, using tap water. The top off is never even 10%, and I do not use dechlor. 
Tap water has 1 ppm ammonia and chlorine from chloramine. 
Yes, over the summer the GH does rise, very slowly. When it rains, I use rain water. This sort of replicates what some fish experience through the year: In dry spells their water gets a little bit harder. When it rains the water gets gradually softer. The amount of change in any one day is too small to test, but over several months it is about 2-3 degrees GH. KH is removed by the substrate, so the pH in these tanks is quite low. Haven't tested it in a while.

... OK, ya got me curious!
KH = 2 deg. 
pH = 7
GH = 6
NO3 = 10
And this was with just one water change about mid summer. I dosed N yesterday.


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## urbach (Apr 16, 2009)

Different livestock react differently. About risk factor, would you want to risk your hundred dollar fish against the cost of dollar dechlorine solution? Have you tried to toping up 1% of water into 40G without dechorinator into Sulawesi shrimps colony? It will wipe out the colony.


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## Diana (Jan 14, 2010)

Good point. 

So, for my reasonable durable fish, top off with less than 10% of the tank volume, no dechlor, tap water with 1 ppm chloramine, about once a week, is OK.


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## WestHaven (Jun 30, 2012)

I'm on well water, but I add dechlorinator anyway because it's supposed to help reduce heavy metals.


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