# full water change



## paul_28 (Jan 20, 2011)

do u ever do full water changes? Im guessing u are worried about losing the good bacteria. It seems everyone does 50percent or 25percent water change. my mate cleans his tank fully every week he say that clean clear water is the way to go.


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## joker1535 (May 23, 2010)

I disagree. Part of the water holds beneficial bacteria. And it shocks the fish when they are removed from the tank every week. Sudden temperature+ph+gh differences affects the health of your fish big time. 50% wc a week and very good filtration will do more good!


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## beN (Apr 21, 2010)

i second that! 50% is ideal not 100%.


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## target (Apr 21, 2010)

Water doesn't hold any benificial bacteria. The filter media, plants, and decor do. Lots of discus keepers do 100% changes daily on their tanks. As long as you are matching the water going in with what you are taking out you won't be shocking your fish.

I have done a 90% change on my tanks before without any ill effects at all. Had my fish laying sideways at the bottom until I filled the tank back up.

Now if your buddy is rinsing out the filter and wiping down the walls he might run into problems.


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## budahrox (Apr 21, 2010)

target said:


> Water doesn't hold any benificial bacteria. The filter media, plants, and decor do. Lots of discus keepers do 100% changes daily on their tanks. As long as you are matching the water going in with what you are taking out you won't be shocking your fish.
> 
> I have done a 90% change on my tanks before without any ill effects at all. Had my fish laying sideways at the bottom until I filled the tank back up.
> 
> Now if your buddy is rinsing out the filter and wiping down the walls he might run into problems.


Ditto!!
What he said 
Cheers!!


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## Adz1 (Apr 21, 2010)

target said:


> Water doesn't hold any benificial bacteria. The filter media, plants, and decor do. Lots of discus keepers do 100% changes daily on their tanks. As long as you are matching the water going in with what you are taking out you won't be shocking your fish.
> 
> I have done a 90% change on my tanks before without any ill effects at all. Had my fish laying sideways at the bottom until I filled the tank back up.
> 
> Now if your buddy is rinsing out the filter and wiping down the walls he might run into problems.


i'm also with Target.....


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## SeaHorse_Fanatic (Apr 22, 2010)

If the pH and temp. were maintained constant between the new & old water, removing the old water (even 90%) didn't shock or kill my fish. I once came home from a short vacation to a 110g barebottom with enough uneaten pellets that it looked like a layer of brown gravel on the bottom. (incompetent fish sitter). I changed out almost 100% of the water & the fish were fine.

Usually, 50-60% is what I prefer to do. I also use multiple filters, so I have lots of good bacteria, even if I remove all the water & clean out the gravel.


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## neven (May 15, 2010)

50% water changes are often done for planted tanks to prevent nutrients we dose from constantly rising. It allows a much more stable constant input of nutrients without a ton of effort needed to fine tune to get it perfect.

Also 50% + for tanks growing out juvenile fish because they release a hormone in the water that can limit growth rate and with some fish (ie discus) stunt them. Plus the amounts of foods fed to grow them out makes a mess.

others do them because they see others doing it.

For a non EI dosed aquarium properly stocked, 20-30% is enough of a change to keep the water clean. For shrimp tanks its even less needed since their waste is negligible compared to a plants uptake. Nitrate tests help determine if we are keeping up with the bio load. If you find yourself not being able to keep up with rising nitrates, you have too many fish, too little filteration and/or you feed too much.

no matter what you do make sure the water matches what you took out. PH, hardness and temp need to be real close to not shock the fish. Even soft water fish need hardness added to the water in vancouver


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## 2wheelsx2 (Apr 21, 2010)

This has been posted before in various places.....should you still be concerned with large water changes.

YouTube - Fastest changing water


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## agresfish (Mar 2, 2011)

I agree , 100% water changes shouldnt harm your fish as long as you use un chlorinated water and dont clean your media filters.. Also helps to take your filters and "swoosh" them around in the tank..


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## 2wheelsx2 (Apr 21, 2010)

agresfish said:


> Also helps to take your filters and "swoosh" them around in the tank..


I would actually siphon out a bucket of water during the water change and swish the media in that and water your garden with it instead of put it back in the tank.


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## paul_28 (Jan 20, 2011)

hi i did 50percent change as too misty greeny in tropical tank. plants were looking chewed by apple snails lol and some parts were yellow instead of green i think plant has had it. do we really need plants in with tropical fish? wondering if its worth getting new plants.


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## Chronick (Apr 27, 2010)

i disagree, when you do 90% water changes, the chlorine in the water will actually kill the bacteria in the filter media and in the gravel. i used to do 70% WC in my tanks and didn't notice anything different but i've opted to do 40-50% WC just to ensure that my tank is healthy


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## 2wheelsx2 (Apr 21, 2010)

Chronick said:


> i disagree, when you do 90% water changes, the chlorine in the water will actually kill the bacteria in the filter media and in the gravel. i used to do 70% WC in my tanks and didn't notice anything different but i've opted to do 40-50% WC just to ensure that my tank is healthy


You're right, no one should be making any water changes without aging their water or using a dechlorinator. In that case, whether it's 5% or 100%, the water will have no chlorine in it. If you're not using a dechlorinator, you're harming your fish and biobed....period.


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## Illbuyourcatfish (Jun 3, 2010)

I do 50% w/c on my 180's every two days, I see great growth from my fish.


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## CRS Fan (Apr 21, 2010)

neven said:


> ......For shrimp tanks its even less needed since their waste is negligible compared to a plants uptake.......


I have EI dosed, CO2 injected, and Metricided shrimp tanks and typically do 60% WC weekly. My shrimp seem to like it. I have done 100% W/C on tanks before too (but on mainly planted, fish tanks). The key is to match water parameters when doing water changes.... AND it never hurts to have filtration overkill ).


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