Co2 And Air Pumps?

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Is it right that they don't mix? If so, can I run my air filters on pure CO2?

I want to convert all my tanks to real plants, mainly to combat the nitrates, but also because they look so much better. The main concern is that every time I introduce plants to the tanks, within a couple of weeks they start to go yellow and then look worse than their plastic counterparts. Sooner or later they just die off.

I've tried the liquid fertilizers, and all they did was to create larger yellow plants, that died off quicker! Lighting is quite sufficient, water parameters are fine, except for the nitrates, which tend to be a little on the high side, (20 - 40), hence the wish for plants, so the only thing left is the co2 level in the water. Weekly water changes control the nitrate levels, and the plecs cope with the algae, but it's getting to be a bind having to do the changes all the time on all the tanks.

If using air pumps, do I need co2 for the plants, or should there be enough going into the water already through the air?

I have been experimenting today, and it seems possible to increase the concentration of co2 in the air by putting a generator inline, but is it needed? Will an excess of co2 cause any problems within the tank environment? How will it affect the PH for example?

My local petstore knows nothing about this subject, and although I have found a lot of info on the subject, no-one has linked the two things together. Has anyone got any experience in this, or knowledge about the subject?

Any thoughts folks?

 

[Lateral Line]

Before worrying about CO2 I should advise you that 90% of beginners to planted tanks loose plants because they have the wrong type of plants and not enough light.

Certainly, CO2 comes out of solution very easily, and if you have a lot of gas exchange at the surface, (air pumps, agressive filter returns, spray bars), you will be knocking CO2 out before it gets a chance to be used. In a similar vane, just bubbling CO2 through the tank will not give it a chance to dissolve, so again, you loose any potential benefits. CO2 is normally diffused very slowly into a tank so it is kept in contact with the water for as long as possible - I inject CO2 into the inlet of my filter train so it can dissolve during it's passage through the various elements.

Adding CO2 normally reduces your pH, but a lot depends on the hardness, (buffering potential), of your water.

I think this thread will be better served in the planted tank section. You'll need to detail your tank dimensions, your lighting strength, type and if possible, colour to get a list of plants that will suit.

 

[timg]

Before worrying about CO2 I should advise you that 90% of beginners to planted tanks loose plants because they have the wrong type of plants and not enough light.

Certainly, CO2 comes out of solution very easily, and if you have a lot of gas exchange at the surface, (air pumps, agressive filter returns, spray bars), you will be knocking CO2 out before it gets a chance to be used. In a similar vane, just bubbling CO2 through the tank will not give it a chance to dissolve, so again, you loose any potential benefits. CO2 is normally diffused very slowly into a tank so it is kept in contact with the water for as long as possible - I inject CO2 into the inlet of my filter train so it can dissolve during it's passage through the various elements.

Adding CO2 normally reduces your pH, but a lot depends on the hardness, (buffering potential), of your water.

I think this thread will be better served in the planted tank section. You'll need to detail your tank dimensions, your lighting strength, type and if possible, colour to get a list of plants that will suit.
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Thank you for getting me into the right section!

The lighting of the tanks is difficult to calculate, as several of the tanks in question share flourescent tubes, but let me give you an idea: tank dimensions: 36" long x 15" high x 8" deep X 2 sharing 1x60" 58W standard flourescent tube. The tube is 4" above the water, separated by a polycarbonate splash cover.

As for the plants, I have no idea what they are, they come from the LFS at 3 for £4.50. The assistants in the shop know less than I do about them, and couldn't even tell me whether they are fast growing or not. We have tried several different varieties, long leaves, broad leaves, ferns, and others. We have tried several different tanks too, with different lighting etc, but all with the same end results, yellow then dead.

Fertilizers from the shops don't seem to help either, but I don't want to give up, and will find a way of getting these plants to thrive. I love challenges, and this is certainly one!

I did wonder about adding a second airstone to the bottom of the filter box where the water enters, so the co2 could work through the filter before shooting to the top, as diagram below, in the same way as you do with your filter inlet, but I'm not sure that it won't just cause an airlock in the filter instead. Would this be worth a try, or is the air filter system just going to defeat every attempt?


The other thing I have in every tank is bubble curtains. They look very nice, but are they working against me? I actually have them coming up behind the plants at the moment, which was my thought behind increasing the concentration of co2 in the air.

Other things I could do to reduce the surface agitation would be to move the filter boxes to the surface, so that the air is released at water level, instead of bubbling through it, or just gently convert the tanks away from air alltogether. The last option would be rather expensive though, one reason I haven't done it before.

 

[timg]

I did wonder about adding a second airstone to the bottom of the filter box where the water enters, so the co2 could work through the filter before shooting to the top, as diagram below, in the same way as you do with your filter inlet, but I'm not sure that it won't just cause an airlock in the filter instead. Would this be worth a try, or is the air filter system just going to defeat every attempt?

I have just set this up a the picture above, and the co2 forms a bubble at the top of the filter box. I expected it to just build up until it blocked the water channel, but instead, excess escapes through the pipe holes in the lid. This seems to be creating a similar effect to the dome method mentioned in another thread, but is also moving a lot of water past the bubble, so should give a similar effect to the powerhead reactor. Is there any way that I can check just how much of the co2 is being absorbed into the water?

 

[Underwurlde]

Hello again.

I'm in two minds as to wether this will work or not. I think the CO2 will bubble away and very quickly pass through the filter section, accumulate at the top and disappear through the hole at the top of the filter box (oops just re-read your post and this is indeed what is happening). It looks hugely inefficient. Same goes for the air. It will increase the efficency of the airstones but not by much. It is not unknown for people to do this, I just think it is not as good as it looks on paper. It is tidy though.

If I were you, wanting to get CO2 into my planted tank:

1) Do away with the air.
2) Attach CO2 to a reactor in the tank:
Spio V Diffuser
http/www.aquaessentials.co.uk/index.php?...roducts_id=1236
Or better still:
AquaMagic Rhinox 1000 (find them on ebay).
3) Oh, & remove the carbon from the filter. Not needed and detrimental in planted aquaria.

Andy

added:
PS Not the same as the power reactor ideas - these work on the Venturi principle to created a negative pressure at the CO2 injection point.