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