I just made a diy CO2 for my tank the other day. After doing research I went with the Hagen Elite (diy) mod for the diffuser. I think it works great because the diffuser can be put on a timer. When it's turned off, it releases huge bubbles that don't dissolve in the water. From what I have gathered, that is the best we can for the fish using DIY.
Now I'm browsing looking for the right CO2 regulator. If you can find the Elite Mini filter, give it a shot. Great diffuser for $10.
I'm going to go ahead and disagree with everyone and say yeah you can run a solenoid on a DIY yeast co2 system. I know I'm going to get my head knocked off but here it goes.
Soda bottles will hold all the pressure thar a yeast culture can produce in 24 hours. They have a burst rating that is surprisingly high! The weak point in the chain is your tubing and its connection through the soda bottle lids. You will get a failure there long before you will get a failure in your bottle. The key to turning off the flow on a yeast bottle us to ensure that you have a relief of some kind so you don't wind up with fizzy yeasty water in your ceiling should you get too much pressure and blow a hose.
I got lucky and found a bad check valve that wont allow any gas to escape below about 30 psi. I have a t in my tubing that connects to a series of valve that I use fir coarse and fine flow control. I use the coarse valve to turn off the co2 at night and the reduced flow keeps a nice bit of back pressure during the day. (The yeast culture seems to be more stable with a bit of pressure on it.)
Now... i have done a lot of testing of my components and culture to get a system that works well for me. I have good control over the amount of co2 going into my tank and can go for days without touching it. However, if you arent willing to spend the time pressure testing your system and plying with the ingredients in your yeast mix then i wouldn't recommended trying. Actually i wouldn't recommend it anyway. Its a bit of work and uf you dont have the tools to set ut up right you will be cleaning the ceiling.
Besides, putting a solenoid on a yeast culture co2 syatem is a bit like putting a blown 350 in a ford pinto, you can do it but why yhe hell should you?! There are much better candidates and if you are going to spend the money you may as well go ahead and spend yhe rest to do it right. I had two months recovering from surgery to piddle around with my tank and all the materials at my disposal so it cost me nothing in time or money.
But to say it can't be done simply isn't true, its just not worth the effort.
can't, some reasons:
1. pressure rating of the container.
2. pressure fluctuate because once cut off flow, co2 will increase at night and pressure rise, co2 injection will not be steady.
there is a possible way, but a 3 way solenoid and a check/release valve that can set the cracking pressure, are expensive!
- if use 3 way solenoid, need to reverse inlet/outlet port and add a check valve on exhaust port as release valve. once the solenoid power off, the outlet(as inlet) to release port open, the co2 in the bottle will vent through the release valve if the pressure reach a certain point(check valve cracking pressure).