With additional DIY co2, will pH continue to drop?

[wonder woman]

I wasn't sure whether this question belonged in WATER PERAMETERS or TECHNICAL. Currently in my 100g tank, I have 1 1-gallon jug of DIY co2 running to a diffusion bell. My pH has dropped since I started using it from about 8 to about 7.6.
My question is: if I add ANOTHER 1-gallon jug of DIY co2 with another diffusion bell, will the pH drop MORE? Or is there a point at which the pH will stabilize?
Thanks in advance!
-Christina

[amanda huggenkiss]

The more CO2 you add, the more your PH will drop. You will need to boost your KH to stabilize your PH. Check out Chuck's CO2 chart for details.

[anonapersona]

At some point, the pH will get harder to reduce because it is hard to hold that much CO2 in the water, it tends to break out. The CO2 you can measure in the water by testing for pH and KH and checking the CO2 chart is the CO2 that is unused. If it is unused, it is in the process of escaping into the air.

Before you add any more CO2 be certain that your KH is high enough to prevent a pH crash. The rule of thumb is about 3 or 4 degrees of KH is desired. Baking soda or coral can raise the KH if your water is in the 0 - 1 - 2 KH range. The acids from CO2 injection can burn through low KH and when it gets to 0, the pH is unstable and can fall rapidly to 6, even 5. Not good for fish.

[wonder woman]

Thanks, anonapersona- I know that our water is hard (there's lots of white mineraly stuff floating in it when it's unfiltered, and the natural pH is 8-8.2), but I just bought a KH and GH test kit, so, when I get home, I will definitely test it to be sure. So, if my KH is 3-4 degrees with the co2 I already have, and remains about the same when i add additional co2, then I'm okay, right?

[Wasserpest]

If you have hard water, you don't really have to worry about pH crashes. Your kH is probably over 10 degrees.

Adding another jug will bring down the pH further, and has the additional advantage that the CO2 production will be more even if you change the solutions in alternating weeks.

[wonder woman]

Ill test my KH tonight to see if my hunch is correct, and post the results. Thanks to you all! I love this site!

[malkore]

I just want to say that yes, adding more CO2 will most likely lower pH more...and that water can hold A LOT more CO2 than fish can tolerate.

However DIY on a tank that size should be pretty safe, particularly since your water sounds like it's got plenty of carbonate hardness.

[Rolo]

Adding more CO2 decreases the pH. It will however stabilize and will not continue to decrease - just as your tank has now stabilized at 7.6. Only uping the dosage will decrease pH further - but then it will restablize again, just at a lower level. With a pH of 8.2 coming from the tap, I'm guessing your KH is over 10.

[wonder woman]

Well, I tested my water last night. It took 9 drops to turn yellow-green, and 10 to turn bright yellow, so I'm guessing my KH is about 9.5. So, does that mean that my pH will probably NOT continue to drop beyond the 7.6 it is now? (Previously dropped from 8.0 when I first added co2).

[Rolo]

Originally Posted by wonder woman

Well, I tested my water last night. It took 9 drops to turn yellow-green, and 10 to turn bright yellow, so I'm guessing my KH is about 9.5. So, does that mean that my pH will probably NOT continue to drop beyond the 7.6 it is now? (Previously dropped from 8.0 when I first added co2).

Originally Posted by I

Adding more CO2 decreases the pH. It will however stabilize and will not continue to decrease - just as your tank has now stabilized at 7.6. Only uping the dosage will decrease pH further - but then it will restablize again, just at a lower level.

[anonapersona]

You can get it lower, but you'll have to add CO2 at a higher rate that you do now. With a large tank, the investment in a pressurized system might be worth it to keep the rate up and stable. Or add another DIY set-up, whatever works for you.

[Unisaw]

If one wants to raise carbonate hardness, how much baking soda should be added at a time?

[malkore]

Originally Posted by Unisaw

If one wants to raise carbonate hardness, how much baking soda should be added at a time?

please start a new thread for your question rather than hijack this post.