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Thread: When do I consider using co2?
05-01-2012, 02:56 AM #1
When do I consider using co2?
I'm currently cycling a 75 gallon tank with plans to do a planted community setup. Already ordered the plants. 23 in all, various swords, needle sagittaria, stargrass, and Brazilian pennywort. I have dual 54w t5 ho lights. I have been reading quite a bit online, but it seems there are a wide array of opinions. Use DIY co2 supplementation. Don't use DIY, use pressurized. Don't use co2 at all. Use Flourish Excel. Don't use Excel... Will my plants grow at all without co2 if I just use ferts? Or is that just asking for an algae proliferation?
05-01-2012, 03:27 AM #2
There is a bit of a balancing act to get planted tanks done just right.
You have to balance the light cycle/output, and the nutrient needs of the plants.
For example, if you have lots of light and nutrients, but not enough plants... you may see algae.
If your light is good, but you don't have enough nutrients, then your plants will grow slowly... but you probably won't have algae either.
When a plant has readily available CO2, it will use up nutrients better, as in faster or easier. Its a good way if you have the first type of set up to have your plants out compete the algae for those extra nutrients.
If you don't add any extra CO2, your plants may not grow as well, but there will still be a little bit of CO2 in the tank... your fish exhale it, just like you do.. so your plants will still grow. They might not grow as well as with it, but there are many people that keep planted tanks without using added CO2.
As for what kind to use... that depends more on what you want to handle for expenses and hassle. DIY is cheap, but requires some work on your part, especially in a medium to large tank. Pressurized has a larger up front cost to buy the equipment, and costs are lower per month/annual but it will be most reliable for keeping CO2 levels consistant. Excel is convenient to buy, but over a longer period of time will have a higher monthly/annual cost.
05-01-2012, 03:56 AM #3
Well then... I may give a DIY co2 setup a try. That way, if I have issues I can scrap it with little capital loss. Plus my son will get a kick out of our little science experiment.
05-01-2012, 05:29 AM #4
I would not use CO2 on a tank that large unless you can use the pressurized system. A tank your size would require 4-6 bottles running on it to give you enough CO2 to make it worthwhile. The DIY set ups are decent enough but were never meant for large setups.
That's a lot of bottles, a lot of lines and a lot of diffusers. That's the same light I have on my 55 gallon and I do not run CO2. I have been having some green spot algae issues since buying the light but it has improved since I increased the ferts. As Trillion says.....a balancing act.
Last edited by Lady Hobbs; 05-01-2012 at 05:32 AM.
05-01-2012, 09:59 AM #5
One word of warning, with any liquid CO2 product, do your research first. Certain plants and certain products don't mix. Easycarbo and vallisneria is a well know problem for example.
05-01-2012, 10:27 AM #6
Your light levels are too low for CO2 to be a limiting factor - CO2 is needed in moderate (3-3+ watts/gal) and especially high light conditions (4 and up watts/gal) and you are not near that with those lights (I assume dual 54 watt units: 108/75 = 1.4 watts/gal.) Further, the depth of a 75 will reduce the intenisty a great deal for low/bottom plants.
That said, a CO2 DIY system will not hurt but it will have no real impact.
Last edited by Cermet; 05-01-2012 at 10:33 AM.
05-01-2012, 10:54 PM #7
Yes, no, maybe, and sometimes.
It isn't reasonable to generate enough DIY yeast CO2 for a 75 gallon tank. You'll have more bottles of water than water in your tank and the sugar cost will soon pay for a pressurized rig. The other is the tank is too deep. You can disperse to the upper layer of water, but the plants are usually below that and bubbles usually float up.
Bio available carbon is what we are looking for when adding CO2 to a tank.
That can be supplied by DIY yeast bottles, a pressurized CO2 system, or a chemical (specifically glutaraldehyde) that breaks down into products that produce bio available carbon. I'm skipping the "natural" products that contain molasses or citric acid.
The most common chemical source is a diluted concentration of glutaraldehyde in water. Dosing generally starts with an initial dose that is higher than the daily dose. It's that initial dose that usually causes issues with plants such as Vals. I suggest skipping that dose and starting from day one with the daily dose. Always work up to higher dosing.
One specific use of an intentional high dose is to kill algae. It has to be intentional though, as it can affect other plants.
The two most common glutaraldehyde solutions on the market are Seachem Flourish Excel and API CO2 Booster. There are cheaper substitutes, but I always suggest people start with one of those, and keep the bottle. The substitutes don't come with aquarium instructions.
05-02-2012, 12:02 AM #8
Thanks for all the helpful responses. I just ordered 2 500ml bottles of Excel and the 1lb macro micro nutrient mix from aquariumfertilizer. Maybe one day when I have a better handle on the hobby, I'll go higher lighting and pressurized co2. The important thing is I don't want to get frustrated or kill fish and plants due to impatience or ignorance. Baby steps...