Turning of DIY CO2 at night

[Zezmo]

I am reposting this from another forum, where someone was asking me if a solenoid can be used on a DIY CO2 setup. A solenoid is usually used to either shut of CO2 at night, via a timer. Or to shut off the CO2 when it has reached a certain level in the tank, via a Ph controller. This method can be used with either of those.

One important factor with DIY is that if you restrict the pressure outflow, you will usually have a very messy failure. This is why most folks let thier DIY run 24/7. It also means that people using DIY do not use things like a Ph meter/controller to limit thier CO2 levels.

The basic idea, it that you use the solenoid to vent off excess pressure at night. This can be on a timer, or on a Ph controller.

It is a simple idea. Had I thought of it a year ago, I might still be on DIY.

 

[Alshain]

The problem with this is, even when the Soelinoid is open, there is nothing keeping the CO2 from going to the tank. You would almost have to have a second Soelinoid before the check valve going to the tank, that would operate on an opposite timer.

Honestly, I never had a reason to stop the CO2 flow to my tank. All it does is save you CO2 in your bottle. DIY'ers don't need to "save" their CO2. CO2 does not displace oxygen, so having it in the tank and not being used does nothing.

 

[JRagg]

The problem with this is, even when the Soelinoid is open, there is nothing keeping the CO2 from going to the tank.

Path of least resistance. If your reactor or whatnot is a few inches below the waterline then it would have no problem bleeding off past the solenoid valve.

Also, is there any purpose in the check valve before the solenoid? Removing that would ensure that any CO2 would bleed off.

I don't plan to turn off my DIY though. I need all of the CO2 I can get.

 

[ryan]

you could also use a gang valve and just open one valve to go to the air and close the valve suppling the tank and also this does not save co2 since its just going into the air it still is used.

 

[Purrbox]

I can see where this would work, but really don't thing it's necessary and it could add to the variable nature of CO2 which encourages BBA. Since the CO2 would need to build up pressure again each morning this could take longer than the allotted time by the selanoid valve near the end of a mix making BBA a greater risk.

 

[Zezmo]

Path of least resistance.

Yup, that would cause the excess to blow out the solenoid.

The question is not whether or not to turn off CO2 at night, and is that necesary. That is a whole discussion unto itself. The question that I was asked, is "Can a solenoid be used to turn off DIY CO2 at night?". I have seen this and similar questions asked on this and other boards.
This method will not conserve CO2 either, but that is not a factor on DIY. Only on pressurized, where you pay by the pound.
This is only for those folks who use DIY, and are concerned over excess CO2 buildup at night. Not a common problem, but I can tell you from personal experience that yes you can have excess CO2 by the AM with DIY, and low surface agitaion, and no airstone.

Airsontes and Surface agitaion are of course other solutions to the same concern. Remember, a solenoid for this purpose can be had for under $5. This is less than even an airpump.

http://www.trianglemachinery.com/index.htm

 

[7Enigma]

The method I use is simpler and does exactly the same thing. I have a $5 timer controlling the PH that runs slightly off-time with the lights (ie on slightly before and off slightly after). My DIY setup is 2 2L bottles connected to a PH where I simply plumbed the CO2 line directly to the intake of the PH. The bubbles get chopped up and keep great CO2 levels when the PH is on. When it shuts off, large bubbles come out the air tube at the top of the PH and hit the surface (about 1" below the water line).

This essentially keeps all of the CO2 from dissolving in the water when the PH is not on, there is no risk of a pressure explosion, and I don't have to think about possible pH issues in the middle of the night.

I'll see if I can dig up a picture or two.....

My timer (the orange thing) which was my parents and is probably older than me!

The PH setup:

 

[Zezmo]

That is a really good idea too. On my main tank i turn off the PH when the CO2 goes off. I think it gives the fish a rest from the extra current.

 

[7Enigma]

Yep, that's another added benefit. I want my fish to be able to "sleep" as much as possible with the least amount of energy expended when the lights are off. When the PH is on they are all constantly fighting a slight current to stay in the same place. This is good for the plants, and probably good for the fitness of the fish, but at night I don't want them to be stressing.