Trying DIY C02... A Few Questions

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aberg12012

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Nov 23, 2005
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Neenah, WI
www.pbase.com
Ok, so I got the supplies, put it all together, and tested my water before starting the reaction.... Woah! :eek: PH was 6.6, dKH 1 (or less...) I have several different test kits that I verified this with. This was the first time I have tested PH and KH on this tank, and it's only been running for about a month. I tested my tap water, and it comes out PH of 7.6, and dKH of 4. So I did a 15 gallon water change, to bring things up in the tank a bit. (Tank is 46 gallons.) After an hour, I retested. It rose to PH 7.0, and 2 dKH. I assume this will gradually drift back down through the night, which is why I plan to add some baking soda also. Obviously, I need to raise KH before trying to inject C02, right?

My next question, is that since my PH/KH values indicate a C02 conentration of about 7.5... if I raise the KH by adding baking soda, will this increase the C02 conentration as well? Or does it raise KH and PH in equal values, and as such the C02 concentration stays the same? If it increases the concentration, were does the extra C02 come from, being that I'm not adding anything but baking soda? Or does baking soda create C02 on it's own?

At any rate, just a general comment: In my shopping today, I also picked up some other supplies, including No-Salt, Flourish, Nutrafin Plant grow (couldn't find stump remover anywhere, so thought this would work for KN03 for now), and last but NOT least... Fleet Enema. And yes... a TWIN pack. :laugh: That was more embarassing than any other "personal care" item I have EVER bought in my life! LOL The things I go through for my aquariums! :D
 
Soda increases KH and pH also, it does not add CO2, though it adds carbonates to the water. Some plants are able to use carbonates instead CO2. Soda is good for increasing buffering capacity of water on CO2 injection. If KH is low, you can inject CO2, but monitor pH levels carefully.
 
Logical explantion... thanks much. :)

Here's the PH/dKH rundown: (All times are approximate)

8pm - PH 6.6, dKH 1

WATER CHANGE

9:30pm - PH 7.0, dKH 2

Added 1/2 tsp Baking Soda. (First disolved in cup of water, then slowly added to tank.)

10:30pm - PH 7.2, dKH 3

11pm - PH 7.0, dKH 2

Lights off at 2am.

2:30am - PH 6.8, dKH 2

I find it intaresting how they drift back down after a few hours. Obviously something in the tank is causing this, and I have a feeling I'm going to be running alot of crushed coral or adding soda untill I fix the problem. I guess we'll see. Maybe a bit of crushed coral in the filter would maintain the KH better than just adding soda. Otherwise it's gunna be a PH rollercoaster ride.
 
The baking soda idea is a good quick fix. I suggest you use some coral as well. It is slower to react and start to raise kH, but in the long term will hold it so that you will be able to discontinue using the baking soda after a couple of weeks.
When you see a steady kH of 3.5°H you will have a safe buffer and know that you've got enough coral working in the tank or filter.

Len
 
Yea... seems like a quick fix that only lasts a few hours in my tank. :D Anyways, added another 1/2 tsp of soda last night after my last testing. Just tested a while ago and it was still at 6.8, and 2 so I slowly added another tsp of soda.

What could be causing my PH and KH to drop like this? The only thing in my tank besides plants and fish, is gravel. I used one bag of florite, one bag of Flora base and the rest regular gravel. Do the plant substrates absorb KH to soften the water or something?
 
"What could be causing my PH and KH to drop like this?"
The pH is dropping because you have very little buffer to hold it while injecting CO2.
You want to be very careful about injecting at night with the lights out with a kH of only 2°H.
I suggest getting 2 or 3 tablespoons of coral into the filter as the baking soda is not holding the buffer for you. It will take some time for the coral to be effective. During the intervening time you might consider discontinuing the gas for the safety of the fish. You may not see much change in kH for a week to 10 days with the coral.

Len
 
florabase

some gravels can change water parameters, you might do some research on Florabase
 
djlen said:
The pH is dropping because you have very little buffer to hold it while injecting CO2.
Click to expand...

Actually that was before I started injecting. I started a yeast culture this morning, a few hours after adding some more soda. PH was sitting at 7.0 and 3 dKH for a couple hours after the last tsp of soda, so I thought I'd give the C02 a try, while keeping a close eye on PH. Anyways, shortly after I also threw in a dead Acro skeleton from my reef tank (one I bleached and was sitting on a shelf as decoration.) I doubt thats really helping matters yet, but it sure looks funny having a bright white Acropora skeleton in a FW planted tank. :D Obviously I plan to add some crushed coral to one of my filter baskets, but was too lazy to rip apart the fluval today so this will do for now.

Anyways, the C02 started bubbling away with in an hour of starting. Increased to about 3 bubbles per second after a few hours. Kept monitoring PH and KH. Stayed steady the first few hours at 7.0 and 3 dKH. After that PH dropped just a slight bit, enough to nottice a color change on the test tube, but not enough change to be considered 6.8 on the color chart... so assuming thats more like 6.9? lol (PH monitor is starting to sound tempting!) Anyways, seems the KH is holding now, so hopefully it keeps up.

NOW my question is this:

I've got the end of the airline right at the intake to my Fluval canister filter, so the bubbles get sucked into the filter. Then every 10 seconds or so, the filter grinds up a chunk of C02 and spits out nice fine bubbles. This seems like the best option to disolve the C02, but I also heard it can harm the rubber seals around the impellar? Should I worry about this or no? I really don't want to end up replacing a $100 canister filter after a year of running C02 through it!

Thanks
 
Well I left for a couple hours. Got back home... WOW! I could tell right away, by how the plants were actually BUBBLING! :D Thats just amazing, and something I've never seen before. However, things went a bit overboard...

PH dropped to about 6.5 (was between the colors of 6.4 and 6.6) and KH stayed at 3 dKH. Which means I shoud have roughly 28 ppm C02 in the tank... a little high. (And that explains the massive bubbling going on from the plants.) Not to mention, that sudden of a PH drop (7.0 to 6.5 in about 6 hours) seems a bit extreme. I guess angel fish really are bullet (or at least PH) proof. So I cracked the top of the 2L bottle to keep from dropping the PH any lower. Also added another 1/2 tsp of soda to bring up KH a little more to buffer things better. I'm really causing quite the PH rollercoaster, but hopefully I can get it in controll before the angels get sick of it.

I also had the 2L bottle in a 5 gallon pail of water, with a power head and heater and was keeping it at 85 degrees, so I'm sure this was accelerating things as well. I did this, because I keep my house at about 65 degrees (yea, not married :D ) and thought that was a bit cold for the yeast? How warm should I keep the 2L bottle?
 
Ok, finally read through all 6 pages of the sticky on this topic. lol Found the answer to my question on temp... sounds like I'll be better off not heating, and getting a longer life from each culture. Sounds like it'll produce C02 just fine at 65, and probably be more steady as well.
 
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