Options for CO2?

[JayZero911]

So it has been a long time since I have asked any questions from AC, but I am getting ready to set up my new 40g breeder. I want the tank planted, I have 2 planted 10g tanks w/o co2 and I want to try it in the 40g. So my Question is about CO2 Booster Liquid. Has anyone used this and is it safe to use with fish/invertebrates? Or will it be simpler to set up a DIY co2 with 2 2liter bottles?

[sunshineb]

I have used the liquid solution in my 40g tall, and I found that it is safe for fish and inverts, however it did not have a huge affect on the plants. It has kept them alive, but I recently ran out and have not bought more in about a month with no change in the health of my plants. I asked my coworker (I work at a pet store with an extensive fish dept.) and he said that a 40g with light-moderate planting would be fine with the Fluval CO2 rated for up to 15g. The fact is that it will work a lot better than the liquid, and it is about half the cost of the one rated for I think it's 60g? So if I were you I'd go with this solution.

[genocidex]

tbh imo, if you arent doing high need plants and high light plants then co2 is kinda not needed. useually if you co2 you will need to fert as well... but there is a great diy fert (for roots) but all in all unless you are sure you need the co2 then dont use it. i have some on hand because i got it for a steal and use it when i do huge w/c's in my 55g. i also fert too

[sunshineb]

tbh imo, if you arent doing high need plants and high light plants then co2 is kinda not needed. useually if you co2 you will need to fert as well...

Why would you need to fertilize your plants because you are doing CO2?

[genocidex]

because theres a balance of co2 used vs nutrients used. if one is lacking then the other is an abundance. if co2 is an abundance then you can suffocate your fish, if the nutrients are too high then it can possibly cause algae. if i had to choose one of those 2 scenarios i would choose the algae any day of the week. this is not true for unpopulated tanks, but it seems there will be creatures in this tank.

so its an issue of wanting all the co2 used up and having as little left over nutrients is possible... also lighting is a big factor as there is only so much photosynthesis a plant can do in low light...

[sunshineb]

because theres a balance of co2 used vs nutrients used. if one is lacking then the other is an abundance. if co2 is an abundance then you can suffocate your fish, if the nutrients are too high then it can possibly cause algae. if i had to choose one of those 2 scenarios i would choose the algae any day of the week. this is not true for unpopulated tanks, but it seems there will be creatures in this tank.

so its an issue of wanting all the co2 used up and having as little left over nutrients is possible... also lighting is a big factor as there is only so much photosynthesis a plant can do in low light...

So I have a 40g with moderate planting levels and 98% stocking. Water params are good, I do weekly water changes of around 25%, my substrate is gravel, and the tank has been up and running for around 6 months. How much lighting should I use, what fertilizer would you suggest, and if I install CO2 will it improve the looks of my plants? (They are brownish in some places and they don't look 100% healthy)

[funkman262]

genocidex is absolutely correct here. Dosing ferts and or CO2 (or liquid carbon) is pointless (and potentially harmful) if you have weak lights and/or slow growing plants. You're essentially trying to supplement what's already being consumed by the plants. If the tank is heavily planted with fast-growing plants, then they'll be consuming all of the nutrients and carbon within the tank at a rapid rate, thus must be supplemented with more nutrients and carbon. If it is heavily stocked with really slow growing plants, or just lightly planted, then the plants could likely thrive off of the CO2 introduced into the tank just from the gas exchange occurring at the surface and the nutrients provided by fish waste. That's why in the second scenario, it's beneficial to aerate the water; you're keeping both the oxygen and carbon-dioxide in equilibrium with the air. In the first scenario, however, if you aerate the water then you're stripping the CO2 that you're dosing back out of the water.