Making A DIY C02 Unit and C02 Mixture Article

[Big Vine]

Yes, I suppose I could do that, Big Vine. That sounds like it would work well.
(Confused? see previous post)

If anyone else happens to find me talking to myself here, could you tell me what you think about what the LFS guy just told me. He runs a place here in my area.

I just went in and bought a bunch of plants, asked him about his CO2 at home (he does DIY). He said he mixes it everyday and it runs about 8-9 hours. His "tip of the day" was to inform me that it would be best to make sure the CO2 mixture bottles are situated above the level of the tank; claiming that, if kept below, the tank water would be sucked into the tank and subsequently returned into the tank along with yeast, which would basically destroy everything.

That's when I asked if he kept an empty space between the end of the tubing (inside the bottle) and the water, upon which his response was to insist that the tubing needed to be submerged!

Please confirm my suspicions about this last part (the tube having to be submerged thing) as being one giant load of bull.

Here I am getting ready to hook my DIY CO2 today---later on---and now find myself second-guessing everything. lol

BV

 

[drumminfish]

I would say that sounds like a load of bull. When the yeast give off CO2, what doesn't get absorbed by the water goes into the air above the water...honestly, I'm wondering what his setup does, since it sounds like he's sucking water into the tank already, if the end of the tubing is submerged. The only way that WOULDN'T be sucking water into the tank would be if there was no suction, which then all that would be is.....a bottle with a tube attached.

 

[iamcowboy]

Also it is my understanding that the inline check valve prevent the yeast mixture from getting sucked into the tank. I have had my first CO2 mixture going for 5 days now. Just do it big vine!

 

[Mahamotorworks]

First off dont submerge the tubing in the Mixture, you are just asking for problems. If his only last 8 to 9 hrs I would throw all of his info out. I have CO2 mix that has been running for 3 weeks. now, the CO2 productions has slowed down, but still going. I am changing it tonight. My Co2 bottles are on the same level of the Tank. I think having them above could cause more problems. If they get knocked over, the CO2 mix WILL end up in the tank. If you use a check valve no tank water should end up in the CO2 bottle. You can use a bubble counter so that no mix ends up in the Tank.

I will get some Photos of my set up tonight when I change my bottle to help you out.

Big Vine but just do it. If you arent happy/nervous about it then take some photos and show them here we will help you trouble shoot.

MAHA

 

[Big Vine]

Whew...that's a relief!

Now...about this "check-valve" business...
I won't be using one of those. I don't think I'll be using a bubble counter either. The only place I have room for the two 2 liter bottles is in the cabinet directly under the tank (on the floor, basically). The cabinet will be cramped with that stuff in there, which means no room for bubble counter.

Guess this means I can only check CO2 level by monitoring pH and listening to 'crackling' sounds from the HOB filter output as the CO2 bubbles get chopped in the impeller?

All in all I'd be looking at roughly 4 ft. of airline tubing on each bottle (~3ft. from bottle to top of the tank, then ~1 ft. to get from the top of the tank to the HOB filter intake, which is where I'll be sticking the tube.

Hope this sounds about right.

I've already got the yeast and lots of sugar, so all I need now is the airline tubing. Couldn't find any stoppers to fit the 2 liter bottles, so it looks like I'll need to bust out the drill and use some sealant.

I appreciate the guidance. I'm sure I'm making this more complicated than it needs to be. I'll be picking up the airline tubing in the next little while, but I won't be back to start hooking things up until later tonight.

BV

 

[Mahamotorworks]

Just drill a hole smaller then the tubing. You will have to cut the tubing at an angle to pull it through. Once it is through It should be air tight. Good luck let us know how it goes.

MAHA

 

[Big Vine]

Will do.
I'm guessing this means the ~4 ft. trip up the tubing won't matter---CO2 should still enter the tank just fine, right? (it is a gas, after all)

Thanks Maha!
BV

 

[Big Vine]

Please check this for me

Big Vine...just do it...If you arent happy/nervous about it then take some photos and show them here we will help you trouble shoot.

Each line of tubing that goes to each HOB intake tube is about 4 ft. in length from the mixture bottles (obviously not hooked up yet)---will that work okay?
Is the positioning of the bottles (i.e. below the tank) okay, or should I expect tankwater to get sucked back into the mixture?

Are the ends of the tubing sticking into the HOB intake tubes properly (i.e. not shoved too far up the tubes)?

Thanks.
BV

 

[tropicalfish]

A Check valve will take care of tank water going into the mixture.

 

[Mahamotorworks]

A Check valve will take care of tank water going into the mixture.

Correct

Big Vine,
Every thing looks good. With the use of a check valve you should have no problem. When you change the bottles out I would pull the Tubing above water level just to be on the safe side.

MAHA

 

[Big Vine]

A Check valve will take care of tank water going into the mixture.

Sounds reasonable, but someone---Grumpy_Marine, I think---said it also inhibited the CO2 from getting into the tank.

Where would you position the check-valve...in the part of the tubing that just goes above the water's surface, or closer down near where the CO2 bottle is?

Maha...so you're saying that I should pull the tubing out of the HOB intake tube so that it is up and out of the water right before I change the CO2 mixture? Or are you saying to make sure that the bottom end of the tubing that goes to the mixture should be positioned above the water level for some reason?

I'm not quite sure what this would accomplish...
Are you worried about tankwater coming out the bottom of the tube and leaking into the bottom of the cabinet? (Wouldn't the check-valve prevent water from travelling down the tube and into the CO2 mixture/cabinet anyway?)

You think it's fine to not bother with bubble-counter bottles (which I really don't have room for anyway )?

Just need some additional clarification on the reasoning behind these steps.

I appreciate the feedback.
BV

 

[Mahamotorworks]

The Bottom end of the tube, over the water level. Check Valves need some pressure going the wrong way to work. I would add the Check Valve about 6 inches from the bottles. You dont NEED a counter. You should be able to tell if they are working by the bubbles hitting the Impellar in the Filter.

MAHA

 

[Big Vine]

Thanks for clarifying, Maha.
I'll install check-valves as per your recommendations.

I'll opt for closely monitoring pH and listening to the CO2 bubbles getting broken-up by the impeller instead of bothering with a bubble-counter.

Now I just need to drink up the two new 2 liter bottles of pop I just bought because I drilled holes that were too big in the first 2 I had.

BV

 

[drumminfish]

Yeah, and what Maha was talking about, if you don't lift it above the water level, and you don't have a check valve, if you're very unlucky you get the siphon effect going on...the very first time I set all this up, I left it hanging there, and came back to a puddle on the carpet and the tube spraying on the floor haha

 

[Big Vine]

the siphon effect...I set all this up...left it hanging there, and came back to a puddle on the carpet and the tube spraying on the floor

Yikes! I'll be sure to keep a close eye on things, and I'll let you know how it goes once I've set it all up (still working on draining those 2 liter pop bottles).

BV

 

[depthC]

Positioning of the check valve isnt critical, its point is to disable flow in a certain direction. You may prefer to put it closer to the bottle or surface of the tank either will do.

A bubble counter is primarily uses in pressurized setups because your worried about putting too much into the tank. With diy you can actually see the air bubble leave the end of the tube and travel to where ever you got it, say a filter intake. A bubble counter is the same concept, so you can see the bubble rate per second usually. Also they probably take up as much space as your check valve, but that all depends upon your model, I guess your reffering to the 20 oz bottle method.

Oh and Big Vine, if you didnt already know you really dont need to drain a full 2 liters only 20 ounces

 

[Big Vine]

A bubble counter is the same concept, so you can see the bubble rate per second usually. Also they probably take up as much space as your check valve, but that all depends upon your model, I guess your reffering to the 20 oz bottle method.

I was going to use the same kind of check-valve that came with a small air pump I'm using for a bubble-wall on a different tank. It's plastic, and it's smaller than my thumb, so I'm not sure what you mean by it taking up as much space as the bubble counter.

Oh and Big Vine, if you didnt already know you really dont need to drain a full 2 liters only 20 ounces

I'm sure there's humor here somewhere, but I didn't get it.
Your recipe for the CO2 mixture at the start of this thread is intended for use in a 2 liter bottle, is it not?

Also, is running two 2 liter bottles on a 38 gal. tank about right, or would it be considered overkill?

I thought it would be good to run one bottle for a week, hook up the second bottle at the end of the first week, and then replace the mixture in the first bottle after two weeks...alternate so that they're overlapping...

I appreciate the feedback.
BV

 

[Mahamotorworks]

Oh and Big Vine, if you didnt already know you really dont need to drain a full 2 liters only 20 ounces

He is refering to If you drilled the holes in the lid of the 2L bottle too big you can use the lid from a 20 oz bottle and it will fit. I feel sorry for you haveing to drink 2 more 2L of Coke. Pepsi would have been much better.

Your check valves are the correct ones. Sounds like the once that I use on my set up.

The refill schedule sounds right.

MAHA

 

[Big Vine]

He is refering to If you drilled the holes in the lid of the 2L bottle too big you can use the lid from a 20 oz bottle and it will fit.

Woops! Makes perfect sense.
I was overthinking things, as usual...

I feel sorry for you haveing to drink 2 more 2L of Coke. Pepsi would have been much better.

Haha!
Well, it kinda works out better this way...
See, my wife got a green bottle of gingerale, and the coke bottles are clear, so now I'll have things color-coded.

Your check valves are the correct ones. Sounds like the once that I use on my set up. The refill schedule sounds right.

Perfect. I'll have to pick up a couple tomorrow.

Thanks for guiding me through all the steps and deciphering what depthC was talking about; even though it shouldn't have required an 'interpretor.' lol

Sorry, depthC...I'm a little slow tonight.

BV

 

[depthC]

lol, honest mistake right. And for the bubble counter, im guessing youve seen the bubble counter made from a smaller bottle, a 20 oz bottle. I remember when i searched up DIY c02 long ago i saw that form of a bubble counter in a few of the articles. What im saying is, by seeing the concept used, you can modify it or reduce its size consideribly. The size of a check valve or maybe a little bit bigger seems very appropriate if your doing it yourself. I got a JBJ one i think with my regulator and its not but maybe the size of two check valves.

For your refill schedule, if you want a continual supply of c02 to the tank you should stagger the time between batch refill between the two bottles. The c02 levels may not be constant between the bottle recharge because both arnt producing in high levels when just one bottle is just beginning its process. But ultimately if you do stagger them your tank will always be supplied with c02 with no lag time between single bottle changes.

Good luck man sounds like youve got a very good grasp on your setup.

Andrew