View Full Version : A few co2 questions

06-01-2010, 05:54 AM
Ok, so I'm just about to start to hook up my DIY co2 system tomorrow. I just wanted to make sure I had everything right before starting.

So far, I have a Red Sea drop checker I got online, a 2 liter bottle, some leftover air hosing, a check valve, baking yeast, regular and brown sugar, distilled water, and baking soda.

I'm going to try to find some easy ways to make a 4 dkh solution for the drop checker with my baking soda and distilled water once I get the whole DIY setup running since I figure I'll have some time before it would reach lethal levels should that happen, but I doubt it would.

My first major question... I picked up a couple packets of baker's yeast since I didn't see any brewers yeast at the store (will probably be ordering online for the next go-around). I got some yeast that said it's highly active. Specifically, Fleischmann's RapidRise highly active yeast. After thinking this over when I got home, I thought that this may burn through the sugar too fast and would possibly produce too much co2 as well. Does anyone know anything about using "highly active yeast" for these DIY co2 setups?

Another question I really need an answer to is: is it necessary to hook up an air stone for night time use if using the DIY co2 that won't ever be turned off? I don't have a problem doing it, since I already have everything I would need to do it, but if I don't have to, I really don't want to. There aren't many plants in the tank right now, but it will be pretty full once it's all said and done. Also if this would affect your answer, my current stocking for this tank (20 gal. high) is:

2 platties, 2 mollies, 5 cories, 5 glo light tetras, 1 BN pleco, a few ghost shrimp, and 5 little fry of unknown origins

And my last question... I have an Aqueon 20 HOB filter running on this tank. I know some of you will say to ditch the HOB if I want to run co2, but I know it can be done and want to give it an honest shot before buying a whole new filter. For any of you that aren't familiar with these filters, it has a little blue plastic piece at the front that can be removed which I'm assuming is for aeration and a place for some more BB to reside. When I remove this to try to get a smoother stream, the water seems a little more turbulent on the surface, but it doesn't fall through the little holes on the plastic piece anymore, so I was wondering if anyone knew from experience which would be the better way to do this?

Thanks to anyone that can answer any of my questions :22: .

Lady Hobbs
06-01-2010, 12:07 PM
Make sure you do not put your diffuser too near your filter intake. I did that once and all the CO2 was pulled out of the bottle into my tank within 5 hours and I had about 14 dead fish in a 29 gallon tank.

Your setup is far more complicated than what I used which was: 2 c. sugar, 2 liter plastic bottle, 1/2 t. yeast. If I wanted more CO2 I increased the yeast to 1 t.

Of course there's the little incident where a tiny piece of yeast got caught in the airline and my bedroom got a bath in sticky solution! I am just not sold on this CO2 business when small errors can cause death and mayhem.

So much hassle when a t. of Excel each day will work just as well IMO.

06-01-2010, 12:24 PM
I think you would be better off with two two liter bottles connected by a T with check valves. It will give you stability as you alternate the bottle you change every couple of weeks.

I would not gas off the CO2 at night unless the drop checker gives you reason to beleive the CO2 levels are getting to high. You will be working hard to get the CO2 into the tank, why gas it all off every night. The chances of an overdose in a 20 gallon tank with a couple of two liter bottles is just about nil.

Use a good quality check valves and back flow should be minimal.

To keep the out flow of the filter from gassing off the CO2 keep the water level very high.

06-01-2010, 08:24 PM
Alright, well I was just taking a couple shots in the dark to see if anyone had the same setup I was about to make. As usual, I'm probably looking too much into it and just need to play around with it. I'll start off with just the one bottle for now just to see if it's feasible, then get two the next time around. Thanks for the advice.

06-03-2010, 09:58 PM
Ok, one more question I just thought of. I just set up the bottle and everything yesterday, and it seems to be working great. I got a nice steady stream of tiny bubbles coming out of my air stone and I get a bubble in my little DIY muck catcher/bubble counter about every 1.5 seconds I'm assuming.

Anyway, I ended up ordering a premade 4dkh solution online to use with my drop checker, so I don't have that set up yet. Once I get that set up and if it tells me I could use more co2, is it possible to cut any of the lines or undo caps on the setup to add a second co2 bottle assuming there's no blockage? I'm not sure how much pressure I'm really working with here and whether or not it will cause a big sticky mess if I don't wait until it runs out naturally.