Cold Water CO2 problem

Grubb

Junior Poster
Apr 13, 2009
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I have a 50 gallon coldwater tank. I get my water from a well and the total gas pressure of CO2 is too high and acts as an oxygen inhibitor (killing the fish). The water is also very hard which leads me to believe that the water is pumped through a limestone substrate. Would a water softener in conjunction with the misting of the water aleviate this problem and is carbonic acid the real problem here?

I'm not sure how clear this and its probably in the wrong catagory but any words of wisdom would be great!

Thanks much!

-Gavin

Tank: 70 gallons
pH: 7.6
temp: 6.0C
hardness: 120-250ppm
Filter: Aquaclear 70 hangon
Cooling: Freon coil refrig. unit
 

Philosophos

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Mar 12, 2009
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Residual CO2 being too high out of the tap is something I can't say I've heard of, especially if you aren't adding CO2. Even letting the water sit for 24 hours should get rid of any toxic levels of CO2. I'm not even sure where CO2 could be coming from to be honest; how have you determined that it's too high?

A water softener is probably just going to be an ion exchange resin that'll swap everything out for salt, which is even worse than just leaving the original minerals in there. If you're on well water you should have a complete test panel listing just about everything relevant. Any chance of you posting it? It would make it far easier to recommend what steps to take.

-Philosophos
 

Tom Barr

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Jan 23, 2005
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I'm afraid you'd have to degas prior to use in barrel etc, venturi atomization etc.
I'd use a wet/dry etc.

Regards,
Tom Barr
 

aquabillpers

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Jan 24, 2005
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This is more questions than answers, I'm afraid.

If there really is a lot of CO2 in the water coming from a well, where is it coming from? What is the chemical source of it?

I believe that water coming from deep springs or wells is usually quite limited as far as oxygen content is concerned.
There isn't a lot down there. Right?

And, finally, if the water does flow through limestone strata, it would have a high KH, depending on the amount of exposure. If the KH were, say, 20 degrees, wouldn't the CO2 be very low and the pH well into the 8's?

Questions, questions, questions.

Bill
 

Grubb

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Apr 13, 2009
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This tank is just one in thirty five that we look after in schools throughout the area and it's located in a small community where there is a single large well that feeds the entire town. We are raising Coho Salmon eggs to the fry stage. The eggs seem to thrive in the well water and we usually have 95% survival. As soon as they are ~2-3 days from hatch, however; we have to have water trucked in from a neighboring community or they all seem to die off.

I have herd of some communities where the water being pumped from great depths gets super saturated with gas and has to be misted to release the gas before being used. We have tried this here but we still get high mortality rates so there must be something else going on.

Tom, I've read your posts on the planted tank forum, and the "Venturi" system seems like it might work pretty well so long as that is the problem we're dealing with. It certainly seems like a good idea for my own tanks!

I should be out there sometime within the month so I'll take the LaMotte kit and get some exact readings that should clarify things (at least for me).

Thanks much everyone!
Gavin
 

Tom Barr

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Jan 23, 2005
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Grubb;41591 said:
This tank is just one in thirty five that we look after in schools throughout the area and it's located in a small community where there is a single large well that feeds the entire town. We are raising Coho Salmon eggs to the fry stage. The eggs seem to thrive in the well water and we usually have 95% survival. As soon as they are ~2-3 days from hatch, however; we have to have water trucked in from a neighboring community or they all seem to die off.

I have herd of some communities where the water being pumped from great depths gets super saturated with gas and has to be misted to release the gas before being used. We have tried this here but we still get high mortality rates so there must be something else going on.

Tom, I've read your posts on the planted tank forum, and the "Venturi" system seems like it might work pretty well so long as that is the problem we're dealing with. It certainly seems like a good idea for my own tanks!

I should be out there sometime within the month so I'll take the LaMotte kit and get some exact readings that should clarify things (at least for me).

Thanks much everyone!
Gavin

Could be degassing of O2 also, but CO2 is common, CaCO3 geology adds lots of CO2 to well water, O2 can be at high levels, particularly if cold and then warmed up some.

I'd try a subsample, degas it it good and then try on the 2-3 day old fry, eggs and hatching should be okay, but once they develop more, that's where there's all sorts of issues.

I'd run it through activated carbon and degas it with vigorous aeration/surface turnover in a holding tank. That would take care of gas issues and any unknown organics. Try at a small scale, see if you get the same results, then scale up, better than trucking water in.

You can also look at the development stage of the fry also in more detail at the 1-3 days stages. Might find answers to the issue/s there.

Since there's a lot of fry to be had, and the issue oif trucking water is large, I'd work from a practical standpoint also, try a subsmaple and degas the water and see. Then AC if that does not work.




Regards,
Tom Barr