# Solenoids for aquarium airtubes - DIY CO2 Baking Soda + Citric Acid



## jrill (Nov 20, 2013)

Why are you going to stop the acid line. You just need to stop the output line from the baking soda.

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## Jayh619 (Sep 6, 2016)

Because, if I stop the the CO2 output line, then CO2 would just Build up like crazy in the 2 Liter soda bottle, and I'm afraid of an "accident" happening from TOO much CO2 build up.

So it would be better to prevent the mixture from combining. I'm assuming.


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## Seattle_Aquarist (Jun 15, 2008)

Hi Jayh619,

Yes you want to try to control the citric acid input not the CO2 output.

It happened on another forum with a hobbyist using grape juice and yeast to do DIY CO2....what to see what happens when you shut off the output?


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## Hoppy (Dec 24, 2005)

The "standard" citric acid/soda DIY CO2 setup is self regulating. If you block the CO2 output, the pressure may build up another 3-5 psi, but then the acid is shut off by the pressure, and it stops. It might be possible to use an electric solenoid and a pH controller or pressure transducer to make it work differently, but that would just introduce a real safety problem. Electric stuff fails.

See http://www.plantedtank.net/forums/2...tric-acid-baking-soda-co2-47.html#post9583601 and the rest of the comments there to get some idea how the "standard" system works.


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## jrill (Nov 20, 2013)

Jayh619 said:


> Because, if I stop the the CO2 output line, then CO2 would just Build up like crazy in the 2 Liter soda bottle, and I'm afraid of an "accident" happening from TOO much CO2 build up.
> 
> So it would be better to prevent the mixture from combining. I'm assuming.


You need to do a little more research. The citric acid method works differently than yeast. 

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## Jayh619 (Sep 6, 2016)

Sorry I take back everything about putting the solenoid on the Acid part. I just re-watched the youtube video for Baking Soda and Citric acid, and it seems like it wouldn't be a problem with putting the solenoid on the CO2 gas output section. So I just basically bought the first item on amazon when you look up "Soleniod DIY CO2" Do you guys think this should work with air line tubing and to block off the air, all I gotta do it set it on a timer to be on, whenever the lights are set to go off? or just use the same timer for both the lights and Solenoid?

I don't know if plugging the solenoid on means it'll block CO2 or allow it to pass. I just ordered all the supplies, so I'm super excited and eager to work on this project.


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## Hilde (May 19, 2008)

Those cheap solenoids on Ebay donb't last long. They overheat before they break down. Best solenoid is made by Clippard.

Some run it 24/7 having an air stone in the tank or putting the output in a bowl.


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## Hoppy (Dec 24, 2005)

Hilde said:


> Those cheap solenoids on Ebay donb't last long. They overheat before they break down. Best solenoid is made by Clippard.
> 
> Some run it 24/7 having an air stone in the tank or putting the output in a bowl.


I have one of those solenoid valves and mine never did get at all hot. It is a very simple valve that should last quite awhile. But, it does seem that the valve works best if it is hooked up so the pressure helps hold it closed. Unfortunately they don't mark the ports so you can tell which one should be the inlet. I disassembled mine to see how it was made, and it was easy to pick out the inlet port that way. I quit using it because I didn't want that complexity yet.


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## Hilde (May 19, 2008)

Hoppy said:


> I have one of those solenoid valves and mine never did get at all hot.


Are you talking about the solenoid, black and silver box, in the attachment?


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## Jayh619 (Sep 6, 2016)

Yup But it has a regular plug for a US outlet, so I'm assuming I can connect air line tubing into it, and it'll do it's job of holding back the gas. At LEAST for the night =) And we'll just find out... that, and I also have a power head attached to a Hydro Sponge, and the power head is causing surface movement so, I'm assuming I don't have to worry TOO much about CO2 poisoning???? 

But would this also defeat the purpose of CO2? Would the surface movement release all the CO2?

Or would there be enough CO2 for the plants still? 

The power head pumps water into a Co2 reactor and then out into the tank causing surface movement?


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## DreamKnight (Sep 17, 2016)

Jayh619 said:


> Are there any online solenoids that I could search on ebay or amazon that would work with Air line tubing? I'm trying to put a solenoid on the tube bringing in citric acid into the bottle that contains baking soda for CO2.
> 
> If you guys have seen the youtube video of the "King of DIY" and the baking soda + citric acid video, that's exactly what I'm doing but I was trying to see if there are any solenoids that could work with this set up for a shut off switch.
> 
> And ALSO WOULD citric acid over time eat away of at the solenoid?????


I grabbed this for $12. This works great. You can see how I connected it with my DIY here in this video @ 2:40s: https://youtu.be/lMm_P-cWMQg?t=2m40s

I just connected it after the Baking Soda line as the pressure doesn't build up to blow anything up during the night. At least, not for me in the past 2 months. :laugh2:

Chung


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## Jayh619 (Sep 6, 2016)

NICE! and also, do you think it's possible to use 2 three liter bottles and add 1/3 more of each recipe??? or???? Cause I'm assuming if a three liter bottle uses the same cap size, then it SHOULD mean I dont have ot change the CO2 bottles as much right???


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## Hilde (May 19, 2008)

Hoppy said:


> I have one of those solenoid valves and mine never did get at all hot. It is a very simple valve that should last quite awhile.


Well mine ran hot. Yours seems to be okay on the DIY Citric Co2. I would not want it on a pressurized system with a tank though.


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## Jayh619 (Sep 6, 2016)

Well, I already ordered the first solenoid on amazon when you search "Co2 DIY Solenoid" So.... We will found out if it runs hot or not.


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## Hilde (May 19, 2008)

Jayh619 said:


> Well, I already ordered the first solenoid on amazon when you search "Co2 DIY Solenoid" So.... We will found out if it runs hot or not.


It looks like the 1 DreamKnight has. Mine did not come with a plug or the connections. I bought it on evilbay. Thus it should be fine for the Citric Co2 system.


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## PlantedRich (Jul 21, 2010)

A point to keep in mind when shopping solenoids is the power used. While some of the energy is spent pulling the solenoid, much of it does wind up as heat so it follows that a solenoid using .67 watt will run cooler than one using the more standard amount of 4 watts. It also follows that getting over into the 7 watts and above may get too hot. It is not a totally easy figure to follow as some are designed with metal fins to cool or plastic housings that make them feel less warm. 
The problem with many solenoids that are designed for other uses is that they do not pull and stay pulled for hours like we want. Furnace solenoids, for instance, pull and stay only while the gas is flowing and then go idle to cool off. 
The heat becomes a problem when it gets too high for too long so that the lube and the moving parts begin to dry or distort so that things stick. Sticking becomes a major problem when it leaves the CO2 on all night if you are running a situation where the fish are gassed by too much CO2.


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## Jayh619 (Sep 6, 2016)

So what wold you guys recommend I type in on ebay or amazon? Or is there a more specific site for the task that I am trying to accomplish?


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## jrill (Nov 20, 2013)

Jayh619 said:


> So what wold you guys recommend I type in on ebay or amazon? Or is there a more specific site for the task that I am trying to accomplish?


http://www.diyco2regulator.com/clippard-mouse-solenoid-with-manifold


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## Hilde (May 19, 2008)

The citric Co2 system does not continuously put out pressure as a Co2 system with a tank. You turn it off and the system shuts down. So a cheap solenoid will work on it.


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## PlantedRich (Jul 21, 2010)

I don't like the noise that many cheap solenoids make. The 110 AC has a bad feature at times when they are not made to be quiet. The electromagnet coil is often made of many small metal stamped plates and glued together to form the metal block. The problem may come around when these metal plates begin to come loose and the 60 cycle electrical power then pulls and pushes them to make a hum. It is called 60 cycle hum. If you stand next to something using a cheap 110AC solenoid, you can hear the hum. Try standing near a furnace, washer, etc if you are not familiar with this hum. 
So I never try to use the 110AC variety and just go straight to DC solenoids. On these the power is not swinging in a 60 cycle way so there is no hum. 
We can' get links through the forum system so it is harder to pass good points across but try looking for "Clippard Solenoid". Just be very careful; when shopping as there are tons of them listed and only one in ten will be the really correct one. EVO-3-12 is a good one if you stick a 10-32 screw in the top port to seal it as it is an exhaust. Then add 10-32 fittings like used for RC airplanes for barb fittings. One for $19.95 appears to have the 10-32 fittings already on but then YOU should check that?? 
Good luck as shopping is one of the hard spots.


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## Hilde (May 19, 2008)

PlantedRich said:


> I don't like the noise that many cheap solenoids make.


You used this on pressurized system with a tank right?


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## Hilde (May 19, 2008)

PlantedRich said:


> EVO-3-12 is a good one if you stick a 10-32 screw in the top port to seal it as it is an exhaust. Then add 10-32 fittings like used for RC airplanes for barb fittings. One for $19.95 appears to have the 10-32 fittings already on but then YOU should check that??


I saw that on evilbay. It is used. I would go for the new 1 and buy the 10-32 fittings from Tower Hobbies.

You will need to get a power supply. Most any 12VDC will be plenty to run the solenoid as they take such low power. Look for one that provides at least 100 milliamps. May be able to find 1 at a thrift store for a few dollars.


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## rk521437 (Dec 24, 2016)

Is it compulsory to fit a airstone to the end of the citric acid input....

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## jrill (Nov 20, 2013)

rk521437 said:


> Is it compulsory to fit a airstone to the end of the citric acid input....
> 
> Sent from my Redmi Note 3 using Tapatalk


I don't think so.

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## That fish guy (Mar 26, 2017)

Just stop the output. It will automatically stop drawing citric acid.
IT IS FOOLPROOF


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