can you give us details on your mixture measurements, and such? I'm kind of interested in trying this as I liked diy yeast co2 minus the mess, smell, and unreliablility.

does the co2 going right into the intake of the eheim cause any issues with the pump? I've heard this has happened with others and really kills the pump.
Thanks!

 

I have been out of the planted game for a bit but I remember hearing that injecting in the intake of you canister filter will kill the benaficial bacteria in the filter media. When I did the DIY Co2 I used 2-3 liter coke bottles connecting to a T to have single out 1/4" out hose connected to a homemade bubble counter then ran the tube to a homemade reactor. The reactor was taking the end cap off my Ehiem 2217 outflow bar and attaching a short hose to it and attaching that to a gravel siphon/cleaner and drilled a hole about 2-3" from top of plastic siphon section(appro.1-1/2"dia.x 6"L) and inserted the Co2 tube and the outflow of water would churn the Co2 and very tiny dissolved micro bubbles would exit the bottom. The tube would have a nice Co2 pocket of gas. It will slow the outflow of the bar nozzle but that didn't bother me. Worked great for about 3 years then started growing coral.

 

Sure.
Bottle A which is 200 grams of citric acid in 600ml of water.
Bottle B is 200 grams of baking soda in 200ml of water. In the coming weeks I may try increasing those amounts 50% across the board to see what happens.
With the eheim and co2 up the intake I have not had any issues unless I have tried to push a lot more co2. A few years ago when I ran a pressure system through an eheim I had to switch to a reactor if I needed 3 to 4 bps, if I remember right. You will know right away if its too much because the impeller will make that rattle noise. When I hear that I figure that's more gas than I want to push through. 2 to 2.5 bps is working just fine in my 2211. I don't see any bubbles coming out the output hose so the dissolve rate must be pretty high. For media in the filter I have it full of all blue course pads with one fine white pad.
I heat bent a piece of rigid tubing 90 degrees and drilled a hole into the side of the intake screen tube to get the co2 in.

 

Nice thread, will be following this..

 

What is the form and the cost of the citric acid?

 

The citric acid I bought on Amazon. Milliard 100% pure food grade citric acid 5lbs. $18.00. Free shipping with prime. Might be a better price out there. I have to admit I did not shop around a lot. The backing soda I just picked up at Walmart. I think it was under $10 for the large arm and hammer box.

 

The citric acid I bought on Amazon. Milliard 100% pure food grade citric acid 5lbs. $18.00.

I get my 5lb CO2 bottle re-filled for less every 3 months.

It's medical grade so I know it's pure and consistent.

 

Would it be cheaper to run this with acetic acid (vinegar)? Or, what about swimming pool hydrochloric acid? (Except that hydrochloric acid is much more dangerous to handle.)

 

Good point, I've always wondered why this is only done with citric acid myself. But would vinegar be cheaper in the long run vs 5lb of powder that you can put in solution? God knows how long 5lb will last lol.

 

I have read a few references to using vinegar. Arguments against seem to range from more expensive to more volatile. I decided to stay with the citric acid because its cheap and the unit I purchased came with starter powders. Also all the units sold seem geared towards the citric acid.

 

Seems like the cost would be minimal. I suppose one would compare it to sugar. But you have more ability to regulate the co2 with this set up, right?

 

I believe that to be correct. I feel I can regulate it as well as I did with a pressure system. Starting Saturday I am going to try turning it off during lights out.

 

Can you post a close up of the needle valve or whatever it is? Im curious how that works exactly. Also the brass ball valve, you installed that, right? So I assume the unit has some kind of pressure release? Close up of that too if you dont mind.

 

And yes I put in the ball valve. Stuff I had and the valve from ace hardware. I thought about using the two little fishes ball valve, $10 on Amazon but I was at ace so,[emoji6]

 

Needle valve

And here is the release valve

 

Thanks. Can you adjust the pressure release to open at a certain level, or is it fixed?

 

200g of soda and acid citric cannot produce 8kg/cm2 pressure. And safe valve will be released at 4kg/cm2

 

It's fixed.

 

How did your plants do when you were running it 24/7? What will happen to the plants when you crank down your bps and run it only a portion of the day? Still trying to decide if its even worth getting the solenoid on a diy setup.

 

Plants look fine 24/7. I will start turning it off just to extend the mix life. Was looking on eBay and found a solenoid for under $15 so I am tempted. The reasons for turning it off at night with this setup are the same as pressurized.

 

If at some point point your needle valve fails or get hold a correct pressure i have an alternative. Its tedious but works. You simply alter the amount of water in your citric acid solution. My recipe is 2.5 cups of water ( close to your 600ml). So i added a 3 cups instead, and reaction slowed to a crawl. 2.75 cups was a little better.
I also tried 2 bottles at 2.5 cups on a one diffuser. That drained both bottles in 1.5 days and sent my Ph down to 6.4... so then i did 2.75 cups and that seemed ok.
Point is play with the amount of water in your acid and you get varying reaction rates

 

Interesting. I was wondering what would happen if you increased all ingredients by 50%. If that might increase output time.

 

thanks everyone, lots of great stuff here to try.

doubling the amount of materials might make it last longer, but it also might become more volatile and not work well to turn off at night and build up the pressure, just thinking that it might be to much pressure depending on what you're using for bottles/lids.

for the diy co2 cap/bubble counter combo thing, how has it been? I've looked at them for over a year but never pulled the trigger on buying on one. do you suggest its worth a try?

 

So yesterday I recharged the bottles with fresh citric acid and backing soda. I have had the unit in operation now for two weeks and running it at 2 bps for 24/7 I have only been able to go 7 days before its empty and co2 production stops. To stay with this unit I feel I need to see two weeks on a charge which was how long I would go with yeast.
With the at least a two week goal in mind I started using the shut off ball valve I installed last night. When I turned off the valve yesterday the pressure gauge was reading just in the green at 1 lb. I was wondering what would happen over night and if I would awake to burst bottles. This morning all was fine and the pressure gauge was still at 1. It would seem that the reports I had read werr indeed correct and if you close the valve the two bottles obtain even pressure so the process stops and does not move citric acid from bottle A to bottle B.
When I opened the valve this morning I expected a rush of co2 that may overwhelm my eheim but that was not the case either. After a few moments the bubble count climbed back to where it had been yesterday.
So far I am very pleased with the performance of the pressure gauge and the needle valve. As to the question if I think its worth getting I'll let you know in two weeks. If I can get two weeks or more between recharge then absolutely its worth it. Much more control over yeast, cheaper than a pressure system. Buy hey, if you have the cash go with a full on pressure system.

 

I have had the unit in operation now for two weeks and running it at 2 bps for 24/7

What are using for bubble counter and where is it placed?

And yes I put in the ball valve. Stuff I had and the valve from ace hardware.

Not clear to me from picture where the ball valve is placed. Had read ball valve on a tee just before the needle valve helps with the needle valve.

 

I would think vinegar and baking soda are cheaper than sugar and yeast.
As long as the pressure relief valve works bottles will not over pressurize.

Coming from the beverage industry, I'll share some bottle info here.
Use bottles intended for carbonated soda not a tea or water bottle.
Soda bottles are blown from a heavier gram weight preform.
They are designed to handle more pressure.
When PET carbonated soda bottles are filled 50-75 PSI is normal.
After receiving a cap their pressure is around 14-30 PSI sent to market.
I can assume this is why 1-2 bar is green on their pressure gauge.
Over time PET bottles in a store will lose CO2, PET plastics are porous.
Thus flat soda from the store, too long on the shelf. The caps don't leak.
PET bottles are blown from an extruded plastic preform.
Seams that you see on the sides of the bottle are not really a seam.
It is a mark from the two halves of the mold, not a weak point.
Weak points tend to be in the feet of the bottle, 5 points the bottle stands on.
Select a bottle without dented in or damaged feet.
Dropped bottles should be discarded and replaced, creases create a weak spot.
Caps come in two varieties lined and liner less.
Pick one with a liner it has an extra membrane to provide a better seal.
Usually water bottles have no liner.

I am going to try this new CO2 method, I think instant pressure is far better.
First day on sugar and yeast is really weak.

 

Thanks for the info on bottles. Currently I'm using mountain dew bottles. I like green. Several write ups advise against using vinegar. Does not last as long and apparently pressure can be a problem. All who have tried it that I could find went back to citric acid.

 

How are you dispersing this right now?

 

Missed this question. Sorry. Currently through my eheim 2211 canister filter.

 

Vinegar is 5% acetic acid (CH 3 COOH) and water.
If too volatile it can be diluted as well.

 

One of the biggest problems with DIY CO2 is waiting too long before replenishing the bottle contents. This lets the ppm of CO2 in the tank water drop too low for too long, and that can trigger BBA growth. It takes self discipline to adapt and follow a rigid routine for replenishing the bottles. When I used DIY CO2, I had bad BBA even with low light, because self discipline isn't one of my big attributes. It worked fine until I got bored with the process and waited too long to do my tank duties. When you use pressurized CO2 the tank of CO2 lasts much, much longer and the pressure gauge on the bottle gives you several days warning that you need to refill it, so laziness is much less likely to get you in big BBA trouble. But, if you can discipline yourself well enough, this looks like a very good low cost CO2 option.

 

I totally agree. Since I am retired being on a regular schedule to change out the bottles is easy. One reason I started up this tank was to have more things to fill up my vast amount of hobby time. [emoji106]

 

Looks like there are different forms of citric acid, monohydrate and anhydrous. Also different grades, food and chemical grade. I wonder if these factors can change how long the reaction occurs.

 

Food grade vs chemical grade shouldn't matter much. Both will be in the high 90's as far as purity is concerned.

The citric acid should be labeled as monohydrate or anhydrous. The only real difference is one of weight. The hydrated form contains about 10% water by mass. If you're intending to use 200g of anhydrous citric acid and 600mL of water, you could use 219g of monohydrate and 581mL of water. It's unlikely that this will affect the outcome significantly.

 

Well I was a little bored so I splurged and picked up a $14 solenoid valve on eBay. Its rated for continuous service so it should work. Came yesterday and I hooked it up this morning. I did experience a small problem with the unit. They use what appears to be a silicon type washer where the bottle goes. Very flimsy. The backing soda side tore a bit and must have leaked. That threw the pressure off which appears to have caused the citric acid to keeping flowing as it tried to equalize the pressure. A trip to ace hardware for a replacement in the form of an o ring fixed the problem.

 

Did you ever get past the 7 day duration or 2 bps? Im doing sugar/yeast on a 20 gallon with two reactor bottles. I can stay at a steady 2 bps changing out 1 bottle per week. If this could do better, either produce more co2 or run steady for longer, then I would be very interested in trying it out.

 

I was in my first week of trying that when the seal leaked. That was yesterday. I had started the two week test last Saturday so I will have to restart that test when the current Solution empties. But judging by how much is left even with the loss of pressure and fluid transfer that occurred because of the seal I will easily go past one week on this load.

 

I was in my first week of trying that when the seal leaked. That was yesterday. Judging by how much is left even with the loss of pressure and fluid transfer that occurred because of the seal I will easily go past one week on this load.

What seal leaked? What was the citric acid and sodium bicarb mixture?

I am using a similar DIY Co2 system on my 20G high. Can't wait to see your progress.

 

Well got nine days out of the last mix which included the above leak. Remixed today so I will see how far it goes at 2 bps just during the lighting period. The $14 solenoid valve I installed has been working really well.