# Top off water



## hachi (Jul 30, 2015)

Hello! Thanks for reading. I recently started using a small fan to help cool my tank through evaporation. It looks like I will need to top it off mid week before my weekly water change. Should I use distilled water to avoid building up minerals? My tank is a 20 gallon long, moderately planted. Sorry if this is the wrong forum. Thanks for any help!


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## quiquik (Dec 13, 2013)

I usually have to top off twice a week for my 50 gal. I just use tap water at right temp or close, and put 1 drop per gallon of prime and pour it in. No problems and have been doing that for quite some time now, even more during the winter months.


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## Audionut (Apr 24, 2015)

Calcium and Magnesium do not evaporate with the water. Less water but same chemical level means those chemicals have a higher concentration in the water.

Topping off with low mineral water is the general recommendation.


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## Argus (May 22, 2013)

Reverse osmosis water is what is usually used to replace evaporation losses. I suppose distilled would be OK, but more expensive in the long run.


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## hachi (Jul 30, 2015)

Argus said:


> Reverse osmosis water is what is usually used to replace evaporation losses. I suppose distilled would be OK, but more expensive in the long run.


I didn't realize there was a difference. Is ro water sold in stores?


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## rragan (Jun 2, 2015)

Yes, I have seen it sold at a LFS in Maryland, House of Tropicals


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## BBradbury (Nov 8, 2010)

*Tank Topoffs*

Hello hach...

When you do your weekly water change, set aside a 5 gallon bucket. Fill it with tap water and add a bit of water treatment. Use this water to top off the tank. No special water is necessary. The bucket water doesn't need to be the same temperature as what's in the tank. I use a small pitcher and slowly pour the new water into the tank. It mixes with the rest of the water in the tank so there's no temperature problem. Minerals won't build up, it's the job of your filtration system and the aquatic plants to remove them.

Hopefully, you're removing and replacing half the water in your 20G every week. If not, work up to it. This is the best way to maintain a healthy environment for fish and plants.

B


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## hachi (Jul 30, 2015)

My tap water is incredibly hard, which is why I was concerned about it to begin with.

I am doing about 30% water changes a week right now. 



BBradbury said:


> Hello hach...
> 
> When you do your weekly water change, set aside a 5 gallon bucket. Fill it with tap water and add a bit of water treatment. Use this water to top off the tank. No special water is necessary. The bucket water doesn't need to be the same temperature as what's in the tank. I use a small pitcher and slowly pour the new water into the tank. It mixes with the rest of the water in the tank so there's no temperature problem. Minerals won't build up, it's the job of your filtration system and the aquatic plants to remove them.
> 
> ...


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## Hoppy (Dec 24, 2005)

In theory you should be using distilled or RO/DI water for topping off, but in reality if you do big weekly or roughly weekly water changes it isn't going to make much difference. I suppose if your house is very warm, you use fans blowing across the water for cooling, and as a result lose 10% of the water every day, then it would make a difference. I top off my tank maybe every 3-5 days, change 40% of the tank water every 2 weeks, and my GH hasn't gone up enough to notice. I have soft tap water though, so I also use some GH Booster with every water change.


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## Argus (May 22, 2013)

hachi said:


> My tap water is incredibly hard, which is why I was concerned about it to begin with.


I'm in the same situation. My water is off the API GH and KH test kit scale. I mix about half tap and half RO water for my aquarium. That puts the hardness numbers somewhere in the 5-7 range.

I purchased a APEC ROES-50 unit from Amazon (their best selling RO unit) for $200 and find it very useful. Tap water was undrinkable because of the taste, but RO is quite good. Don't have to buy spring water any more. When I wash my reading glasses a quick rinse in RO prevents spotting. 

The only downside is that the reserve tank holds less than two gals. So I often run out when doing water changes and have to let it recharge for a few hours.

I've seen RO water sold in health food stores. You bring your own bottles and they fill them up at their RO machine. I saw someone bringing a grocery cart full of 5 gal. plastic jugs into Whole Foods, so they may have it as well.


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## al4n (Nov 18, 2008)

It it not recommended to drink pure ro water unless you put it back through re-mineralizing filter. 

Topping up evaporated water loss in your tank with RO water is recommended to stop build up of TDS, as mention above it doesn't really matter if you are doing 40-40% water changes weekly.

Sent from my SM-N910G using Tapatalk


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## Hoppy (Dec 24, 2005)

Has anyone ever run into problems with their planted tank when they used tap water to replace evaporated water, and also did 40-50% water changes every week or two? I can't remember ever reading about such problems. Perhaps, if you are breeding some fish or shrimp that will not breed if the TDS creeps up, you may have seen problems. But, I really doubt that an average planted tank will be adversely affected.


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## quiquik (Dec 13, 2013)

Hoppy said:


> Has anyone ever run into problems with their planted tank when they used tap water to replace evaporated water, and also did 40-50% water changes every week or two? I can't remember ever reading about such problems. Perhaps, if you are breeding some fish or shrimp that will not breed if the TDS creeps up, you may have seen problems. But, I really doubt that an average planted tank will be adversely affected.


No Hoppy I have not had any problems with tap water for top offs during the week maybe 2 gals little more in the winter months and I do 50 percent wc every week. Tank is a 50 gal and ei dosing, black blasting sand substrate with osmocote plus, co2 with 48 inch sat plus pro lights on for 6 hrs at roughly 65 percent power.


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## al4n (Nov 18, 2008)

With minerals building up i was more talking about shrimps and specific fish that has an effect on TDS, planted tank wouldnt matter at all.

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## Argus (May 22, 2013)

Hoppy said:


> Has anyone ever run into problems with their planted tank when they used tap water to replace evaporated water, and also did 40-50% water changes every week or two?


How many people really do that water changes that large and that frequently? 

My 30g usually tests at zero ammonia, zero nitrites, and zero nitrates. I tend to go a couple weeks between water changes and don't do much more than 25%. Is there any reason I should be more aggressive about water changes?

At the moment I'm more concerned about the plants needing more nutrients.


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## Darkblade48 (Jan 4, 2008)

Argus said:


> How many people really do that water changes that large and that frequently?
> 
> My 30g usually tests at zero ammonia, zero nitrites, and zero nitrates. I tend to go a couple weeks between water changes and don't do much more than 25%. Is there any reason I should be more aggressive about water changes?
> 
> At the moment I'm more concerned about the plants needing more nutrients.


I do 50% water changes on a weekly basis...


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