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How does CO2 affect ph levels?

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Those who say they cant, Never will !!!

Hi,
As you inject CO2 it forms a weak acid and the pH will
lower. How much depends upon how aggressivly you add
CO2, and what the KH (Carbonate Hardness) is. As a rule
you want a KH of at least 3 before adding CO2. The
carbonate will buffer the acid.

Frank


-->>> The Confidence of Amateurs, is the Envy of Professionals <<<--

Thank you Frank,

Is there a test kit for KH??? I set up a diy CO2 and when I got up this morning my fish were gasping and the ph had gone from 7.0 to 6.2.

I took it straight out, I'm assuming I had too much CO2 in there and the lfs tells me to put a tap on the hose leading to the airstone ... but im worried that the bottle might explode and all that sugar mixture will get all over the place ... ugh what a mess that would be to clean up

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Those who say they cant, Never will !!!

Hi,
Yes, there is a test kit for the KH values. I have
purchased the Aquarium Pharmaceuticals, Inc. "Master
Test Kit." It contains everything you need to test the
pH, Kh, GH, Nitrites, and Ammonia in the tank.

Your LFS is correct, if you find your fish gasping in
the morning then the CO2 level was really high. And, you
are correct when you discuss a DIY CO2 system. That is one
of the major flaws of that kind of delivery. A gang valve
is an option and probably the better idea. Have one valve
set for the airstone, and use the second valve to vent the
CO2 to the atmosphere. That way you don't have to readjust
the CO2 delivery each morning for a given amount of
bubbles. Saves time and hassles.

Frank


-->>> The Confidence of Amateurs, is the Envy of Professionals <<<--

Thanks again for that information Frank.

So a gang valve is actually like a double adapter with one airway going to the airstone and the other going into the atmosphere, thats pretty logical when you think about it. So if I wanted to I could actually turn off the CO2 at night? How would that affect things being as plants dont absorb CO2 in the dark (is that right???)

Would the ph remain neutral with the addition of CO2 if I get the flow correct or will it still become acidic?

I'm still a bit hesitant to try this again. I'll take the info on board and might give it another go.

Cheers
Crush

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Those who say they cant, Never will !!!

Frank, just another question ... would the excess CO2 thats being released into the atmosphere give off an odour?

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Those who say they cant, Never will !!!

Hi,
If you were using a "double" gang valve, you would connect
the input side to the CO2 generator, one output would
go to the airstone, and the second would need no hose
at all. Close both outputs, and then open the one for
the airstone till you get the desired amount of bubbles
out of the stone.
When you want to stop injecting the CO2, you would
then open the second valve all the way and the gas
would then escape into the atmosphere. This is
because the airstone offers resistance and acts as
an obstruction to the flow of gas while the second one
has no resistance and the gas will take the path of
least resistance.
In the morning when you want to restart injection,
simply close the second valve and the gas will be
forced into the airstone again, at the same rate that
you set up.

Any time you inject CO2, it forms a weak acid and will
lower your pH. How much of a swing between no CO2 and
CO2 depends upon the KH of your water.
If the KH is 3 - 5, then the water will mollify
(buffer) the acid and the swing should be less than
1 point. IOW change from say 7.0 to 6.9 or maybe 6.8.
No big deal and easily handled by the fish.

Yes, the CO2 is the result of the fermentation of the
yeast and sugar, and it smells like old beer (to me).
How much it would affect the room (your nose) depends
upon the size of the room, the duration that it is
vented into the room, and the rate at which it is
being generated.
A fresh batch puts out more CO2, faster, than an
old batch.
Which, by the way, is going to cause you to have to
be constantly adjusting the valve that goes to the
airstone to keep the rate of bubbling near constant.

Frank


-->>> The Confidence of Amateurs, is the Envy of Professionals <<<--

Thanks for all your info Frank, really appreciated.

Cheers
Crusha

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Those who say they cant, Never will !!!

I was going to set up my own DIY co2 injector kit on my 5' tank. After putting up a thread on here titled CO2 Injector, I have now gone against the idea of putting CO2 into my tank and instead have bought a double light unit along with my single light unit, have a total of 112 watts in fluro tubes and will be fertilizing on a regular basis.
I'm hoping I will now not only have happy fish but also happily thriving plants. Thanks to the 'stranger who takes no responsibility' for helping me out. Maybe you can help out here upikabu
http://photos.yahoo.com/shedevil_90
Cheers BubbleLover

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My Fish like swimming all day long,
They love my bubbles 'pop' on their bum!
http://photos.yahoo.com/shedevil_90