Couple of newbie questions, also a possible DIY CO2 design.

[bs6749]

1. How much CO2 should be in a 55 gallon moderately planted freshwater tank ideally? (80 degrees, pH 7.0, KH/GH both 80ppm)

2. What is the best test kit (or a decently priced and reliable one) for CO2 levels?

3. For a DIY setup, what is the best way to evenly distribute the CO2 throughout the tank or is this not much of a factor?

4. How much CO2 should go into a tank when it is being added? By that I mean how much and how often? I have heard 3 bubbles every 5 seconds as well as 1 bubble every 5 seconds...

I had an idea for a setup but I am not sure that it will work. This may have been posted before because it seems fairly obvious to come up with, and with that in mind I am wondering why it is not more common. I have searched the forums here and have seen nothing on it. I have seen the basic setup of a 2 liter bottle filled with water, sugar, and yeast but I was wondering if there were a more efficient way of making CO2. Then I thought why not baking soda and vinegar in the bottle? I have heard people say that the yeast may only last 3 days or so but have also heard of it lasting weeks in producing CO2. Is yeast preferred because of its slow and steady production of CO2? Would there be some way of me regulating the flow of CO2 reliably and cheaply by using just baking soda and vinegar? I realize that this is a quick reaction, but I thought that if I had a glass bottle to better withstand the pressure I might be able to get this to work. I could use some sort of a check valve system to slowly let out CO2 when I need it and have it stored in the bottle when I don't. Let me know your thoughts on this as I am ready to try it out to see if I can get my plants to grow better. TIA.

 

[evercl92]

Just my imput
1) 12-30 ppm

2)don't know that any are "decently" priced. all the ones I've looked at, that give an actual numbered result (rather than 'low' 'medium' or 'high') are expensive

3)I use a penguin 1140 to launch the output of the CO2 tank across the aquarium

4)I didn't do DIY very long (I got a killer deal on pressurized soon after I started DIY), but the info I gathered pretty much said you need one 2L bottle for every 20gal. That being said, I would say 3 bottles would do you good. I had 4 bottles going, cranking out 2 bubbles/sec. At that rate, I was able to keep algae from growing. The plants are going crazy. So when I switched to pressurized, I set it for 2 bubbles/sec with the same or better results. My tank is very heavily planted though, check here.

I think the actual rate is variable, and quite dependent on the immediate factors in your particular aquarium. I've read that you can judge CO2 level by: [1] if the fish are gasping, you have too much and [2] if you have algae you don't have enough.

I would start with 2 bottles, piggy-backed into the same output into your tank. Add a 3rd (or 4th) in a week, and judge plant growth then.

I don't see the baking soda / vinegar idea working... it's simply too quick and unless you have a aluminum or steel tank, you're not going to be able to capture and control the release of the gas. My DIY bottles lasted between 2 and 3 weeks each.

 

[Purrbox]

1. Ideally you want at least 30ppm of CO2 in the tank reguardless of the size of the tank. With a KH of 80ppm, you'll be aiming for a pH of 6.7. However with your current test results of pH 7.0 and KH 80ppm, your current level of CO2 is being measured at 14ppm. Unless you are already injecting CO2 into your tank, this means there is a buffer present in your water that is invalidating the pH/KH relationship.

2. Both AP and Hagen should be just fine for the necessary KH and pH kits.

3. DIY CO2 is not recommended for a 55 gallon. As far as getting CO2 into the water reguardless of source, a powered reactor or mist is your best bet. Then as long as you have good water circulation, the CO2 will be fairly evenly distributed through the tank.

4. This will vary based on a large number of factors. You water, how large the bubbles are, how efficient your diffusion method is, etc. You best bet is to test you CO2 levels and figure it out from there.

With DIY CO2 the goal is to get steady high levels of CO2. Most DIY methods are going to be variable by nature, including Yeast. If the level produced aren't high enough, then you are courting algae problems with BBA being the most likely to show up.

Here's a prior discussion here reguarding Baking Soda + Vinegar to produce CO2.