CO2, When to?

[sanddigger]

I have two tanks with plants. A 29g with two amazon swords (1 year) and a 55g with some newly added anacharis. I would really like to "plant the tanks up", but I am not sure when CO2 is needed. Is it the amount of plants, type of plants or a combination of both? I'm sure I'll have to change the lighting too. I'm soooo confused.:confused:

[marek313]

I think the ammount of CO2 is directly related to the ammount of light you have over your tank. You dont really need CO2 until you have at least 2watts/gal. It will help at any light level even below 2w/g but it doesnt make as much difference. I had swords growing at 1w/g but not really all that great and anacharis will be fine under 1w/g. Now they are under 2.75w/g with home made CO2 and Seachem Excel and they are doing great. 3 month old ruffled (martii) is about 14-16 tall (you can see pictures below my sig) I'm not sure what kind of light you have but I would think about that first and without strong enough light CO2 is not recommended.

[Chrona]

I think the ammount of CO2 is directly related to the ammount of light you have over your tank. You dont really need CO2 until you have at least 2watts/gal. It will help at any light level even below 2w/g but it doesnt make as much difference. I had swords growing at 1w/g but not really all that great and anacharis will be fine under 1w/g. Now they are under 2.75w/g with home made CO2 and Seachem Excel and they are doing great. 3 month old ruffled (martii) is about 14-16 tall (you can see pictures below my sig) I'm not sure what kind of light you have but I would think about that first and without strong enough light CO2 is not recommended.

I agree. Though plants will benefit from CO2 at almost all levels of light (since it is usually the limiting factor), the pH changes/other issues with CO2 probably don't make it worth it until over 2w/g