Co2 help

[Gbr4774]

I set up co2 on my angelfish tank and prior to setup ph was 7.2 kh was around 120ppm I believe and after a week of co2 ph 6.0 kh 0 and I'm not sure why, drop checker stays green and I'm running 28ppm co2 4 drops per second 55 gallon aquarium 

[Daniel]

The carbon dioxide you are adding to the water combines with water to make carbonic acid. Carbonic acid after exhausting the kh of your water begin to lower the ph. This is likely why you have a pH of 6.0 and a kh of 0.

PH is also a function of the time of day you measure it. If you measure in the morning, pH is much lower than if you measure in the afternoon. It can vary by a full point over the course of a day in a planted aquarium.

[gardenman]

I tend to think you can have either a plant-centric tank or a fish-centric tank but it's very hard to optimize conditions for both in one tank. If you want a plant-centric tank, then you should inject CO2, use intense lighting, fertilize heavily, and grow the most exotic plants you can find. Your plants will thrive. The fish, maybe not so much. If you want a fish-centric tank then no CO2 and keep plants that thrive without CO2. (And there are a lot of them.) If you look at the plant-centric, carefully landscaped tanks, by and large the fish are minimal. Do a Google image search for "aquascaped aquariums" and you'll see what I mean. They might have a small school of small fish but the tanks are clearly not fish-centric. They're showcases for the plants and the fish just happen to be there. 

Injecting CO2 is going to alter your water conditions in ways that aren't ideal for fish. It's the same in humans. Some terrestrial commercial greenhouses inject CO2 for the plants but humans working in those greenhouses often have to wear air tanks and respirators to breathe well. The CO2 injection helps the plants to grow and suffocates insects who could damage the plants. (There are no bug air tanks out there, so they die. It's an effective form of growth stimulating and also pest control in commercial greenhouses.) Too much CO2 can suffocate your fish, cause ph crashes, and can literally eat your equipment in the tank. Those who inject CO2 seem to have more impeller issues with filters due to the carbonic acid.

To me, the use of CO2 comes down to what you want as a tank. Is it to be fish-centric or plant-centric? My tanks, jungles that they are, are fish-centric. The plants are those that thrive without CO2. (And boy do they thrive. I'll be weeding out a bowl full in a few more minutes.) I worry more about the fish than the plants though, so the fish are my priority.

If you try to balance a system to optimize it for both plants and fish, then life gets more complicated. Some say if you shut off the CO2 an hour before the lights go off and have an air pump that comes on when the CO2  shuts off, that it can off gas the CO2 and prevent a ph crash. Then wait an hour after the lights come on before starting up the CO2 again and shutting off the air. It starts to get more like a job and less like a fun hobby when you try to balance out both. There are many more ways for things to go wrong and more stuff you have to monitor when you use CO2. I've played with DIY CO2 and have considered using the commercial units, but I don't really need more growth than I'm getting now.

[Socqua]

50 minutes ago, Daniel said:

PH is also a function of the time of day you measure it. If you measure in the morning, pH is much lower than if you measure in the afternoon. It can vary by a full point over the course of a day in a planted aquarium.

Wow that's good info; I did not know it fluctuated that much in a day. I did know CO2 affects pH, so I should have known lol. I assume that is in a fairly well planted tank? And in a tank with no plants the pH would be more steady?

I've been super nervous to see my pH from my water supply vary from 7 up to 8 and then doing water changes and affecting the pH. Knowing that a change of 0.3-0.5 pH during a gradual water change is less than a typical day is really good info!

[Socqua]

10 minutes ago, gardenman said:

There are no bug air tanks out there, so they die.

Had to google that just to be sure 😄 ... maybe not 100% true:

Come Up for Air? Not These Insects, Which Carry a Bubble as ...

[gardenman]

2 minutes ago, Socqua said:

Had to google that just to be sure 😄 ... maybe not 100% true:

Come Up for Air? Not These Insects, Which Carry a Bubble as ...

It's a bit challenging for a bug to do that in a greenhouse though.