Gas equilibrium in tap water vs. outside atmosphere stressing fish?

fjf888

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Oct 29, 2007
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Northern Virginia
Tom,

I had an interesting conversation with my LFS owner. It started off with how he was impressed with the plant cuttings that I was bringing for trading. I explained to him EI and the 50% water changes I do weekly and how my plants are responding. He was worried that the 50% water changing is stressing my fish. He stated to me if changing more then 25-33% of the water at a given time that it should be let to stand out over a day. The reason was water under pressure in pipes has a gas imbalance (nitrogren, oxygen CO2) with the water in the aquarium and outside atmosphere, and that changing a significant amount of the water would have a benz type affect on fish. He said that hobbyists are not aware of this, but fish farmers are. He says most fish farmers run their tap/well water through a degassing chamber before it empties into their poinds. Have you heard of this or has research been done on the effects of various gasses affect fish? Since this sort of cuts right at EI and your background is scientific I would like to hear your thoughts.

Thanks

Fre
 

VaughnH

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Jan 24, 2005
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Obviously I'm not Tom, but as my parents used to say, "the proof is in the pudding". Many, many people now do 50% and bigger water changes routinely, most by filling directly from the tap. We don't suffer from fish deaths as a result. Heavy rainfall doesn't cause mass die offs of fish in nature, and those are major water parameter changes.
 

fjf888

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Oct 29, 2007
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Its not really fish deaths, more like a high stress item. I pretty much agree with you, but I guess his argument water flowing from tap being under a certain amount of pressure, which is different from the rain falling from the sky, and that for the gas in the water to come into equilibrium with our environment the water needs to age for a day. It may be complete crap, but generally this guy has provided me useful information through the years, so I am giving it some consideration and pose it to the experts.
 

atrixnet

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Feb 5, 2007
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It would be good to know. I fill my tanks straight from the tap, adjusted by feel and thermometer for temperature so as to not cook or freeze the aquarium populous.
 

fjf888

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Oct 29, 2007
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I talked with someone from another forum who owns a fish store in Florida, who has good relationships with a couple of the fish farms in Florida. He said they never heard of this so I chalk it up to an interesting hypothesis with no proof. Plus many of the experts here change 50% or more of their water weekly with no problems (Hoppy's Post). So I am going to continue to follow what has been working well thus far to me.
 

nwfishinfool

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Jun 22, 2007
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I am from being an expert in this hobby but I am pretty observant. I set up my aquarium 12 months ago this Christmas, and started practicing the EI method in June and I have noticed that my fish seem to really enjoy the water changes. As soon as the gravel tube is put into the aquarium some of them follow it around and when I start adding the fresh water they dart in and out of the flow. Many of the pairs start spawning behavior almost every water change now. I match the water temp with the new water so I do not believe the spawning attempts are related to temp changes.

I love this hobby, it can be as intense or as simple as we want it to be.

Hi, my name's Mike and I am a planted tank addict!
 

neil1973

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Dec 17, 2005
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It is a potential issue for commercial systems where ground water sources that are under high pressure are being used. Also air leaks into the pipe work of recirculating systems where water is under very high pressure can cause these problems. However i have never heard of any situation where a domestic water supply has caused these problems for aquarium fish with any amount of water changing including 100%.

cheers
neil
 

Tom Barr

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Jan 23, 2005
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Well, some fish in cold temps can get excess gas bends.
But depth of the water etc is a real issue.
Few of us have deep tanks like 2 meters or more.

Also, Discus farmers do 70% water changes in many cases, no issues.
So the type of fish seems to be part of it, the tap water source also can play a role.

Still, I've never had issues with well/under ground water sources, or deep water intakes from lakes. the gas seems to equilibrate rapidly, and does not cause the bends in tropical fish, the gas is going out of solution, not into solution when we add it to our tanks, so ...........

Not also, we add CO2............at higher ppm;s than amibent, yet water changes do not cause gas bends with tap either way as well.

I look at the observations and how we might test such hypothesis before assuming such a hypothesis appears reasonable.

As with anything concerning a "hypothesis", it must be falsifiable to test to it.
Does truth exist?
Does God exist?

What test can you show that it does?

None really. Faith is about all you got.

Gas influence on fish due to water changes?
Yep. Try it and see.

No need for faith here. Such trite hobby level matters:)

Gas bends do exist in fish and under some cases, however, I've yet to see it in our specific examples. When studies are used, logic or things that sound reasonable, make sure they are specific and apply to your specific case.

Namely tropical fish.
BTW, even Reef tanks greatly benefit from 70% water changes.
So it's a pretty wide spread observation across many differing Phyla.

Regards,
Tom Barr