[burr740]

Decided to hook up a bit of CO2 for my 75. :bounce:

Not sure if I actually want CO2 on this tank or not, but I have been thinking about it. So before investing in a pressurized system, I decided to hook up a bit of DIY to see if I can get a feel for how things react.

Im aware of the challenges when it comes to DIY on larger tanks. Im just hoping to get a consistent 15 or so ppm - using minimal bottles. I believe that is possible with a leak free system and good diffusion.

Ive been experimenting for a few months on a 20 gallon using a single 2L bottle. I found that the following recipe will run 16-17 days, before starting to slowly taper off. After 3 weeks, it's still generating a lot, just not as much as originally, like 2 bubbles every 3 seconds instead of 1 per second.

So considering a duration period of ~2 1/2 weeks, before a slow decline, I decided to start out with three 2L bottles. The plan is to change out 1 bottle every week. Im willing to go to four and change two/week, perhaps using a bit more yeast, but Im hoping that wont be necessary.


The Simple Recipe:
2 cups sugar
1/2 Tsp regular baking yeast
1 Tsp baking soda

I activate the yeast first in a small bowl of luke warm water. Sprinkle in a tad of sugar and stir it gently with a fork. Then let it sit for about 15 minutes, stirring it again every 5 minutes or so. In the meantime I mix up the sugar/soda/water in the 2L bottle. I fill it about halfway with room temp water and shake it up well. Very well. Then fill it the rest of the way up (to just above the top of the label) and shake it again until everything is dissolved good. Then I pour the yeast mixture in. I dont shake it up any further.


Now on to the build pics...

Here is the finished gas separator/bubble counter, a 1.89L Juicy Juice bottle with a big wide cap. That was important because I wanted the lines going in separately, to be able to tell exactly what each bottle is doing.

To create the seals, I used a combination of check valves, and air tubing connectors, the kind that come with those cheap discard-a-stone diffusers, like you see in the picture ^. Having a check valve on each reactor bottle allows you to disconnect one without de-pressurizing the entire system.

It is based on the following method (Thanks to DarkCobra, who I believe originally came up with it some time ago)

15/64" hole
Push tubing through
Insert the connector, which expands the tubing in a tapered manner
Push it back into the cap, HARD

100% mechanical. No mess. No leaks.


Finished separater top:

Finished reactor bottle cap:

All hooked up:

 

[burr740]

Diffusion is kind of a two stage event. First there's a piece of regular cotton ball packed tightly into the CO2 line, which then runs into the intake of a small, upside down power head.

Hard to tell in the pic because my light is aimed mostly toward the back, but the power head is mounted at the very front of the tank. The bulk of the mist stream hits the ground about where the center Crypt is, and then sorta just disperses all over. I think it is pretty efficient. You can barely see any bubbles unless you get right up close. Then it looks like a Sprite can exploded in there.

It's been running now for two days. Already seeing a bit of pearling, mostly from the Ludwigia and Bacopa. I only have med light (2 T5HO) so Im not really expecting to see much. Everything seems to have really perked up though, that much is obvious. Tops of the Mermaid Weed turned a different color virtually over night.

I havent done a full degas test with the same water yet, but PH seems to be down about .7 from what it normally is (taken in the middle of photo period) Correct me if Im wrong, but that's like low 20's ppm? If so that is fantastic. I'll know more in 24 hours.

Also ordered a glass ADA drop checker from Amazon, apparently gonna be 2-3 weeks before it arrives though :/

 

[tricken]

it will help but with a tank that size you will want a bottle soon i did diy for a good 90 days it was fun but then mixing every week sucked.

 

[mistergreen]

The little bottle isn't going to add much CO2 in a 75G. The 3 bottles is best for a 30G. Maintaining them will be a pain.

Your plants look great with what you have now so the bottle might give them a little extra CO2.

 

[FishieNewbie]

awesome!!! how did you maintain such healthy plants without CO2? I am a newbie and from what I am finding so far, lighting and CO2 are what we need to get a beautiful tank like yours.

 

[burr740]

awesome!!! how did you maintain such healthy plants without CO2? I am a newbie and from what I am finding so far, lighting and CO2 are what we need to get a beautiful tank like yours.

Thanks. The main thing I did was spend a lot of time reading this forum! :red_mouth

Lighting is obviously important, but most important is to have the right amount, as in, enough but not too much. Tons of plants out there that will thrive under low to medium lighting (what I have) and no CO2.

Check out this thread there are hundreds of examples- Low -Tech Show and tell

 

[Hoppy]

A 0.7 drop in pH due to CO2 means the ppm of CO2 in the water went up by a factor of 10 to the .7 power, or about a factor of 5. Assuming the water had 3 ppm before the CO2 was added, you would have about 15 ppm of CO2 now. For low medium light that may be all the plants can use. But, I don't recall anyone reporting on test results to see what ppm of CO2 is optimum vs light intensity. It would be an interesting test to try, but difficult to do well.

 

[burr740]

Thanks for the info, Hoppy. I arrived at the low 20s going by this bottom right chart, which seems to use a slightly different multiple somewhere.

 

[Bandit1200]

Before I went fully pressurized this is almost exactly what I had set up for my 29G. At that rate you will have a pretty steady flow of CO2. It did not strike me as being particularly difficult to keep up with changing out one bottle every weekend while I was doing other tank maintenance. By doing it this way you always have at least 2 bottles pushing a good amount of CO2 and by using the check valves for each bottle, you don't lose any time regaining pressure from a swap.

 

[Hoppy]

Thanks for the info, Hoppy. Around 15 ppm is the target range Im shooting for, consistently of course. I arrived at the low 20s going by this bottom right chart, which seems to use a slightly different multiple somewhere.

That bottom right chart is incorrect. It assumes that the ppm of CO2 is directly proportional to the pH drop, and it is actually proportional to 10 to the pH drop power. A .5 drop in pH actually means about 9.5 ppm of CO2.

 

[burr740]

Thought I'd post an update, since it's been about a month. Still running 3 bottles, changing 1 per week. Plants have really exploded. Im having to prune the ludwigia and bacopa every week because it hits the surface. Drop checker stays a relatively darkish green, slightly brighter when the lights first come on.

Between that, degas test, ph/kh chart, Im fairly confident in a ppm of at least 15, maybe a tad higher. Regardless, it's made a huge, HUGE difference in the growth rates and color of things.

Here's a couple pics. Ive re-arranged the tank some since the last ones.

Drop checker at the end of photo period. Picture-wise it's a fairly accurate color representation, maybe a shade lighter in person.

 

[burr740]

Here's a little growth update, 9 days since the last pics.

Gonna have to bush hog the back right corner pretty soon. I cut the Bacopa back a few days ago. It had hit the surface to the point it was shading the L Glandulosa.

 

[korbinavery]

So?

First off, gorgeous tank! I've came back to this thread multiple times. I also have a planted 75 and have duplicated your method as it is simple and straight forward, how has it worked out for you so far?

 

[Maryland Guppy]

Thinking of a DIY CO2 option also.

 

[burr740]

First off, gorgeous tank! I've came back to this thread multiple times. I also have a planted 75 and have duplicated your method as it is simple and straight forward, how has it worked out for you so far?

Im glad this thread has been of some help to you

It has really worked great. Ive been very pleased with the results, esp for a tank this size. Never had any algae issues, or any other nightmare usually associated with DIY CO2.

About a month after the last post itt, I increased it to four 3 liter bottles, changing out 2 per week. Also switched to using a reactor instead of a power head for diffusion (no more sprite water!)

Here's a few pics. These are probably the last ones of this tank using DIY, I have all the parts for a pressurized system, just havent hooked it up yet.

Needs a trim:

Post trim:

Thinking of a DIY CO2 option also.

It can definitely be done. The main things are a leak free system, good diffusion, and multiple bottles with staggered start/change times to maintain a consistent bubble rate. I was averaging in the range of 26-30 bubbles per 10 seconds with the three 2 liter bottles. Using the four 3 liters, Im averaging 39-44 bubbles per 10 seconds, or right around 4 bubbles per second. That is as consistent as Ive been able to get it, not bad for DIY iyam. Thanks for having a look

 

[Dan110024]

If this setup doesn't convince someone that DIY CO2 doesn't have to be messy or difficult, I don't know what will. How have you found making up a mix every week? I hear some people complain, saying it's too much work, but I have always loved tinkering and looking for something to do with the tank.

This thread has topped it off for me. Time to get a second tank setup!

 

[burr740]

If this setup doesn't convince someone that DIY CO2 doesn't have to be messy or difficult, I don't know what will. How have you found making up a mix every week? I hear some people complain, saying it's too much work, but I have always loved tinkering and looking for something to do with the tank.

This thread has topped it off for me. Time to get a second tank setup!

Thanks, mate. Im glad to hear that.

As for the task of changing bottles once a week, it only takes about 10 minutes, and most of that is just waiting on the yeast to proof (Im still just using regular bakers yeast) I also like tinkering with tank related things, so I dont mind the bit of extra work.

Having a check valve on every bottle is a big help, because you can disconnect them at any time without depressurizing the whole system. I usually do the changing out at the end of a photo period. That way by the time lights go on the next day it's kicking full strength again.

The main draw back is cost in the long run. With the 3 liter bottles Im using 2.5 cups sugar, and a heaping 1/2 tsb of yeast. So that's 5 cups of sugar and probably 1.5 tsp of yeast per week. Fast forward 10-12 months and you could buy an entry level pressurized system for the money spent. Extremely low start up cost though.

 

[Wasserpest]

Nice postings. Uncomplicated and really inspirational. CO2, whether it comes from fermentation or a pressurized bottle, makes a huge difference for plants, at any aquarium size.

There was a guy from India who had something like a 350 gal tank with DIY CO2. :hihi: He shut it off during the night, and collected the CO2 that was produced during the night in collapsible containers, which were weighted down with bricks, so over the course of the day they would deflate.

I used to do DIY CO2 on my 100gal tank. After a year or so, I just invested in a cheap 10lb bottle, regulator, and solenoid. It wasn't as much the cost of sugar and yeast, as the weekly bottle washing and changing that got me in the end. :tongue:

 

[burr740]

Thank you for the kind words Wasserpest. And holy crap at DIY on a 350 gal tank, I bet that was site to behold...

-------------

Ive now gone pressurized on the 75 gallon. Still doing it on my 20H grow out tank though, the one I experimented with initially before setting it up on the 75. Just now I dug out some pics for another thread, so I figured might as well post some shots in here as well.

In particular I wanted to point out a little known fact, that Aquaclear HOB filters make an excellent CO2 diffuser. Specifically due to the way water passes through the media, from bottom to top. Other HOBs, any cartridge types, they dont work because the co2 can off-gas in the rear water chamber.

AQs on the other hand, can offer 100% dissolution, esp when pre-diffused with something like a cotton ball or chopstick in the end of the co2 tubing. This is an AQ20 @ 2 bubbles per second. Any bubbles you see are from plants pearling, zero coming out the filter. Im sure larger models could handle more.

Here's a few pics. Ive since switched to using a 3/4" piece of chopstick in the co2 line, these were taken using a cotton ball.


First planting

3 weeks

To clean up the look of things, drilled a hole and ran the co2 line up higher in the intake

Lights are two 18 watt 5000K spiral CFLs in aluminum dome reflectors. I used 23 watts for a while but they were a little too much. This tank is mainly used to propagate cuttings and experiment with different things, so the contents vary.

Not counting plants, I put this tank together for roughly $100. Petco $1 per gal sale, Aquaclear20, Black Diamond blasting sand, Clamp-on reflectors/cfl bulbs from Lowes, misc DIY co2 components...


Currently runing two 1.89 liter Juicy Juice bottles, same recipe as in OP, changing out one bottle per week.

 

[benealing]

What size hole did you drill, and how did you attach the air line tubing? Also, what are you referring to when you are talking about prediffusing with a chopstick or cotton ball? Where do you put it etc?

Looks great!

Ben