Co2 Concentration

[max1]

Hey everyone!

I'm planning on installing a CO2 system as a carbon source for my plants. I've benn doing some reading and planning but I still have a few questions:

Some of the CO2 present in the tank dissociates to form carbonic acid which brings the PH level down right? Does this decrease in Ph increase with a higher concentration (don't know if that's the right term) of CO2. If it does, then what's the safest concentration for an aquarium (for both the PH and the fish) ? My KH is about 7-8°d.

During the night, plants (and the fish) use O2, so to minimize the PH swing I'm going to aerate during the night. Would this be sufficient?

I'm using a yeast CO2 generator, so I think that risk of over supplying the tank in CO2 is low but still, better safe then sorry!

All advice is welcome !

 

[SuperColey1]

You don't say what size your tank is, what kind of diffusor you are using, how much light you have, or how good your water circulation is!!

Assuming you have a tank 20G or less with under 2WPG then 1 DIY Co2 should be OK as long as you have a decent diffusor and your circulation is good.

With Yeast CO2 you will struggle to reach 30ppm let alone overdose. People who try to get more out of their yeast kits don't overdose but end up with yeast mix climbing the hose into the tank!!!

Therefore I wouldn't worry about Ph swings, Aeration or anything else.

If there is a gentle ripple on the surface you should be getting enough O into the tank which allied with the good circulation which the CO2 will also need should spread nicely through the water.

Ph swings are not too much a cause for concern.
Yes with high CO2 the Ph can drop but at 30ppm it will drop about 1ph. The fish will not mind this and it will be a gentle adjustment.

With pressurised most of us have solenoids that turn the CO2 off at night (to save money) and the ph swing doesn't affect our fish.

With yeast kits there is no option to turn off at night as you need the solution to keep going until its weekly change. If you try and start stop it each morning and night it will just run out of gas (quite literally)

Therefore due to the impossibility of overdosing and the need to keep levels up yeast kits should be run 24 hours with aeration only if needed.

Andy

 

[max1]

Yeah sorry about the lack of info there. My tank's a 10G with 1.5WPG. The CO2 isn't really a necessity right now. My hood holds only one bulb so I think I'm going to get a new one, so soon I'll have 3WPG and at this point the Co2 will be needed.

Alright, looks like I don't have to worry about too big of a PH swing. The kit will be entirely DIY and I'm inserting a DIY liquid,solid-gas seperator to keep from cloggin the tubes or getting yeast into the water so I don't think I'll have to worry about that either.

I have very good circulation (my pump is rated for up to 150ltr). As for the diffusor, I think I'm going to put the tube in the filter intake. now I have a question about this. Will this cause the impellor to vibrate alot, and if yes do you think it will be enough to damage the mechanism?

Thanks for the quick answer!

 

[SuperColey1]

Are you using an internal or external filter?
Are you using a spraybar?

Andy

 

[max1]

Internal filter. The Rena iv3.

 

[SuperColey1]

If it is like internal filters there is a seperate hole in the 'out spout' with a cap on it (similar to the ones you get to blow up inflatable things)

If so you can take the cap off it and jam a hose connector in it, the connect you airline to it. The bubbles will then get to the 'white' turbulent water befopre being blasted out of the output.

If you are using a spraybar it will 'fragment the bubbles for you and blast them around the tank.

If not using a spraybar, attach a small piece of mesh over the end (like the small mesh moss often comes in) which will seperate the large bubble for you.

If you don't have a spraybar attachment for it, and the output is round and not square, have a look in P@H where they sell the fluval internal ones for a fiver.

Andy

 

[reggieschuey]

As for the diffusor, I think I'm going to put the tube in the filter intake. now I have a question about this. Will this cause the impellor to vibrate alot, and if yes do you think it will be enough to damage the mechanism?

I am not sure about internal filters. It might, for canister it rarely does unless its a cheap filter... The sounds are not noticeable anyways.

 

[max1]

Here's a pic of my filter.

I'm not sure what you mean by spraybar as opposed to out spout. isn't it the same thing. Anyway, since it's a DIY generator it won't generate that much CO2 and I think I should be OK just putting it into the input.

What do you think?

 

[SuperColey1]

What your filter has is just an output. A spraybar is an attachment that on an external would replace an output (these days most seem to come with spraybar instead anyway) and on an internal the can be connected via some hose to the output although with yours being a funny shape I don't think this is an option.

However. I notice that on the top of your output there is a thin piece sticking up!. Is this a tube that could be used to connect your CO2 tubing to? If so give irt a try.

Andy

 

[max1]

Yeah, that's what I thought when you told me about the nozzle,... but do you think it will be enought to dissolve the CO2? I really can't afford any waste.

 

[SuperColey1]

There is debate on wether the bubbles want dissolved=ing or if mist is the way to go.

Certainly most of the people that I tend to acknowledge more than others seem to suggest that mist is the most efficient and if this is so then it would possible be OK for you if you cout fit the CO2 onto that nozzle and then somehow cover the end of the output with gauze so that water will still get out and the bubbles will be 'shredded' wither that or try it your way and see what happens.

Try both see which one works best

andy

 

[max1]

Ok, thanks for all your help!