CO2 ph not fluctuating = bad thing?

[bman]

I have hooked up DIY CO2 to my tank for over a month now. For the first mix, I noticed a slight drop in pH from 7.0 tp 6.7. That seemed to be a good thing from my research. I kept that mix for about three weeks, and during the last week, I noticed that the bubble rate went down from about one bubble every 10 -15 seconds to about one bubble every 30-40 seconds. I changed it out, and this second batch that I'm on seems to be producing in the 10 second range but the pH is not dropping as before. It remains constant at 7.0.

I also have plumbed the tube into my HOB filter intake. That is the way I can count the bubbles, but hearing the the crunching sound of CO2 bubble into the impeller.

Unfortunately I do not have a KH test kit, but have been looking for one around here and no one seems to sell them. I have found them online, but do not prefer to go that route yet.

Is the lack of pH drop something I should be worried about?

 

[Purrbox]

Unfortunately the answer is maybe. This can mean one of two things. Something has caused your KH to shift so that even if you're getting the same CO2 levels it's resulting in a different pH. Something has happened causing lower CO2 saturation levels. I would strongly recommend that you pick up a KH kit as soon as possible. While it may be possible to troubleshoot without one, you're making it much harder on yourself that way. If you don't want to order one online, check with your LFS to see if they would be willing to special order one for you.

 

[7Enigma]

I'm concerned that you are not producing near enough CO2 in either batch. The general concensus is that 1-2 bubbles PER SECOND are required to get to acceptable levels (15-30ppm). Of course the method of delivery and agitation of the surface will affect these levels, but I cannot imagine 1 bubble every 10 seconds is creating even close to the desired amount.

I would first tackle the bubble rate, and then determine how much CO2 is actually present in the tank. A KH kit will definatley help you in determining how much more you need, but IMO you first need to get a much faster bubble rate going.

What is your mix composition and bottle size for the CO2 generation?

 

[bman]

I have one 2 liter bottle with 2 cups sugar and close to 1/2 tsp of granular yeast. I have bloomed the yeast in a 1/2 cup warm water for about 30 minutes before adding to the bottle.

1 to 2 bubbles every second! Wow. The only way I can tell the rate is by listening to the filter churn up the bubbles; I do not have a bubble counter.

Do you think I need to add another bottle? I will be checking the lfs tomorrow for a KH kit.

 

[rich311k]

With a 20 gallon, you should be running two bottles.

 

[fish_4_all]

I use two 2 liter bottles and easily get 1 bubble a second if not 3-4 for about 4-5 days and then it drops to about 1 bubble a second but I change out one bottle every week. This keeps my levels at 45-60ppm with piping it into my AC HOB.

You really need that KH test because it can change for what seems absolutely no reason and it could be way too low to be injecting CO2. Mine fluctuates between 4 and 7 dKH and I test mine regularly because I don't want it to drop enough to start to harm the fish.

 

[mr funktastic]

what mixture do u use fish for all? that sounds awefully high for DIY. so u use alot of yeast?

 

[Purrbox]

Actually it's not really accurate to use bubbles per second as a measure for CO2 output except in your own tank. The bubble size could vary greatly from one setup to another depending on what they're coming out of. One bubble in my setup, might be 5 or more in someone else's setup. Even then with all the other variables some tanks require more CO2 to be injected to reach the same levels of CO2.

 

[fish_4_all]

2.5 cups of sugar and 1/2 tsp yeast.

 

[bman]

OK I picked up a KH test kit today. dKH = 4

With a pH of 7.0 that puts my CO2 at 12.

That sounds quite low. Even when I was first producing and my pH was 6.8 that was not much better. I guess I will have to drink another 2 liter of Mug Rootbeer to get another bottle up and running.

It may also help if I can get the water level up so the HOB doesn't make more of a surface agitation like I have been reading in these threads.

EDIT: Oh yeah, I forgot to ask...How could I raise my KH level? Baking soda?

 

[rich311k]

Yes, Baking soda would work, but a KH of 4 is fine, no reason to mess with it.