Viable CO2 Injection System?

[J double R]

I use a limewood airstone (commonly used with protein skimmers) on the end of my airline. the bubbles are easily compared to an expensive co2 diffusor, are cheap and easily replaceable once clogged, and coupled with the placement near my canister filter's output, results in the tiny bubbles staying underwater for an extended period of time, bringing nearly 100% diffusion.

running an air pump through the bottle, may likely upset the anaerobic life cycle of the yeast, which doesn't need any oxygen to create the byproducts of co2 and alcohol. I'm not sure what the result would be, but I don't believe you would yield the same results (or if you did, it would be excessive and inefficient) as if you used the co2 from a sealed system.

 

[nickmcmechan]

Thanks, Nick. I keep a 30gal as well. What's the difference with the 1l bottles?

Sorry, should have explained the reasoning behind the multiple bottle.

When I had a 2 litre bottle my CO2, kH and pH levels rose and fell as the CO2 levels rose and fell from one bottle, as the yeast activity rose and fell and eventually died off.

I didn't want this, I wanted a more stable environment for my inhabitants...fish, plants and all.

So what I run now is 3 x 1 litre bottles. I change the mix on different days so that the peak of CO2 from one bottle coincides with the trough of CO2 from the other. This way I maintain more consistent levels of CO2 from my DIY setup.

I was running the CO2 in from my internal filter. I have removed that to another tank which is not CO2 injected now, so I now run it from an airstone.

A dedicated CO2 airstone is OK, but I would combine it with air. I put my airsone at the other end of the tank from my ugf output where I have a still spot of surface water. Its tucked under a load of plants so that when the bubbles hit the leaves they will disperse. This is also near the output of my cannister filter spray bar, to help duisperse the CO2 throughout.

However, I do plan to switch to a CO2 ladder for better dispersal.

The output of my ugf is not straight up and has a 'head' on it which points horizotally. I point this to the rear of the tank to minimise surface agitation, which works OK. So, I still get the benefits of my ugf which I like.

So, in summary I setup the CO2 output in the quietest part of the tank. I use 3 x 1 litre bottles. I change the bottles once per week each, one on a Tuesday, one on a Thursday and one on a Sunday. Thsi lines up with my pwc schedule. I plan to change the arstone to a glass diffuser.

I would appreciate opinions on my methods, but is does get me 10ppm + CO2, which is good enough for me combined with bright lighting, a reflector, root tabs and liquid ferts...

 

[amhodge]

Lots to consider!
JR, thank you for the basic lesson in life sciences. I think you're absolutely right.
I'm going to steal some ideas from you, Nick. I'm thinking of putting my airpump line under a gravel-to-surface pile of wood. I expect this will limit surface agitation as the bubbles take longer routes and disperse in smaller increments (and improve the look), then I can set my CO2 at the other end of the tank, in a still spot as you said under some plants, or under my filter as JR suggests. Though instead of tucking the airstone under plants to disperse the CO2, would it not be as effective to bury it in the gravel?

 

[nickmcmechan]

I've not tried the under gravel thing yet, so interested to hear opinions on this anyone?