DIY CO2 impossible to control

i61164

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Apr 14, 2017
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So I bought a cheap diy co2 kit off Amazon for about $15. It screws onto 2 2 liter soda bottles and I put citric acid in one and baking soda in the other. The recipe works fine and generated co2 which I can diffuse into my tank. The kit I purchased has a pressure gauge that is on top of the citric acid bottle and a needle valve that is on top of the baking soda bottle. The pressure reading is about 1.5 and can change, but seems to stay reasonably consistent. The problem is that the bubble count will not stick for any length of time. I can set it to one bubble per second or whatever with the needle valve, but in less than 5 minutes it has changed to one bubble every 5 seconds. Meanwhile, the pressure reading is unchanged. This happens even with fresh bottles of citric acid and baking soda. I think it's just a crappy needle valve, but I'm not sure what to do about it besides get a pressurized system (which I probably will do). I expected the cheap diy system to need frequent adjustments, but not every 5 minutes. At this point it's almost unusable. Any suggestions?
 

rajkm

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Adjustment of needle valves is not instant. When you open a needle valve it lets pressure out at a higher rate until it normalizes. Which means you will think it's one bubble per second but once it normalizes it may give you a looser reading. Same happens the other way around. You have to keep dialing in every 15-30 mins until the bubble count does not change after 30 minutes.


Also if your input pressure changes, so will the bubble rate.


Thats another her reason we use solenoid, so you don't have to dial it daily. Or using a needle valve with vernier handle so you can dial it daily for a given pressure.


Investing in a good pressurized system is a good way to go if you don't want to deal with all this. Also let's you enjoy the plants and concentrate on growth etc v/s worry about co2. I have gone thru the same process to realize that everything else is a waste of time and money.
 

i61164

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Apr 14, 2017
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I'm assuming there is no good way to add a quality needle valve to my cheap $15 system. The needle valve it came with is basically attached to the bottle cap with some airline tubing. I've tried to adjust it repeatedly with no real success so I'll have to find a better solution. I guess the good news is that I didn't waste tons of money on this first attempt at CO2. My inclination is to just skip to the end and buy and custom co2 rig. I've been reading some old threads and I looked at what is commercially available. It looks like the commercial regulators I found on Amazon did not get great reviews and so I'd rather not spend $150 and get something I'll end up being unhappy with. It does not look like building a custom regulator myself is the best option for me. I think with enough effort I could follow the directions I have found on this site, but it seems like way to much work. It took me quite a while to figure out how to plum my overflow to my sump, so building a regulator is level of difficulty that I might better avoid. Plus a lot of the information is many years old and I don't know what is currently available and have no way to get special deals on parts. I don't see any regulators offered by Bettatail for the last 3 years, but flowerfishes list several for sale. From a consumer standpoint, the choice is not very easy. The prices tend to range from $350-500. The difference between them and whether those differences would matter to me is not clear. From my research, I gathered that a vernier handle on the needle valve is desirable, but apart from that it looks like a tough choice between these high end regulators from a noob to the hobby without any background in engineering.
 

burr740

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The regulators on Amazon like Aquatek, Milwaukee, Azoo, whatever, can be hit or miss. You might get a good one or you might get a piece of junk. Ive had both experiences with Aquatek. They're all about the same, mass produced in China.


A good middle of the road if you dont want to drop mega bucks is the GLA Gro series. http://greenleafaquariums.com/co2-regulators.html


rajkm is absolutely right. I ran diy on several tanks for about a year, had decent success but it's a real pain in the ass to constantly fool with.


On top of all the effort involved, even under the best of circumstances it's going to be inconsistent as new mixes become old mixes. There's absolutely no way around it.
 

i61164

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Apr 14, 2017
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Thanks for that link. It's nice to see a commercial source of good regulators as a comparison point for these custom builds I see here. Some of flowerfish's regulators are refurbished, but since high end regulators should last forever that's not an issue. The GLA GRO series starts at around $200 for a single stage brass regulator. Once you look at the dual stage stainless model you are up to $625. Flowefish has comparable regulators for less than $400 so that seems pretty good. I guess the only downside to buy from an individual here is you don't get that 6 year warranty that you get from GLA. On the other hand, I'm not really sure if I would notice a real difference between the stainless dual stage vs the brass single stage option. GLA claims that their single stage regulators will prevent end of tank dump, so if that's true maybe the only difference is aesthetics and that won't matter with it sitting inside the cabinet. The only other selling point I see for the GLA (besides a $200 price point and the warranty) is the modular manifold expansions which allow you to add additional CO2 outputs for multiple tanks. That could be a nice option in the future but I don't even have room for multiple tanks close together. Choices, choices...
 

burr740

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Fwiw my GLA Gro 1 DOES have a little end of tank dump. It's not extreme like you can get with an Aquatek or similar, but there is a substantial increase that happens all of a sudden if I let the tank run bone dry.


All in all though, Im very pleased with it after about a year. Their customer support is great too.
 

anandjm

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Mar 30, 2017
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I had the same issue with controlling the co2 rate. I solved it by using two needle valves. I have the second one fixed at the input of the bubble counter which is what is adjusted and locked in to the required bubble rate. The first needle valve is used to turn on and off co2.
 
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i61164

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Apr 14, 2017
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That's an interesting idea. I'll probably try that for now while I continue researching and saving up a few hundred dollars.
 

i61164

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So in spite of what I said about not building a regulator, I made an impulse purchase


imagejpeg



This was $285 dollars cheaper than anywhere else it was being sold and if I get serious buyers remorse I could return it to Amazon. Maybe I can turn this into a build thread . Based on what I know so far, I think I will need to figure out how to attach a solenoid and a metering valve. So here comes my first super noob question. Why are there two knobs in this picture. I have been looking at pics of regulators for days and the regulator itself usually has one knob or screw to adjust the working pressure. A second knob would be on the needle valve. But this pic is of the regulator only, right?
 

Jason King

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I don't know much about Harris regulators but I'm sure thats a big bargain and they sold it at the wrong price missing a zero.. it should have cost over $500?


Someone else will confirm this.


As for the solenoid you are correct it does not include it but it can be purchased separately.
 

rajkm

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The second know is a metering valve. It's not as precise as we need. You can just take it out, or leave it and use it as a additional valve to get close to desired bubble rate and use a fine metering valve to dial in. I threw mine away.


solenoid get a new Burkert 6011.


there is a regulator build sticky around that should help.
 

i61164

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Apr 14, 2017
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Latest update: I got my regulator ($70 shipped) and I'm collecting the other parts I need. Meanwhile, I tried adding a second needle valve to my diy CO2 setup, but I couldn't get it to work any better then before. The other day, the plastic tubing popped off the needle valve and water started spraying onto the wall from the baking soda bottle. It was sticky too which I don't really understand. So I've completely abandoned the diy CO2 system. But it's going to take a while to build my regulator, so in the meantime I am dosing flourish excel. I bought a Burkett solenoid with buna seal on aquariumplants.com for $71 (shipped) with the plug already wired. The solenoid alone is about $50 + shipping. I could wire it myself, but it was only an extra $12 and I figure it was going to cost me a couple bucks to buy my own plug and it seemed worth it to save the additional shopping and labor. I also got used 5 pound CO2 tank from Amazon for about $55 shipped and called local places where they fill/exchange. Every local place that sells the empty tank charges about $80-85, so Amazon saved me about $30. It should cost me about $15 to get the tank filled. I still need a metering valve, a check valve, and all the fittings to put it together. I've been looking up metering valves with vernier handles. These tend to be the really fine adjusting ones that we need. I have found swagelok and Parker products available for $115 and up on Amazon and Sigma Aldrich. Once I make up my mind and get one, I'll be ready to put all the pieces together. A friend of mine is a chemical engineer and told me about a local place called F.P. Fensel. If I bring all my parts to them, they have all the fittings I'll need and I think they'll have the check valve as well. Some of these places are like warehouses and you have to know the part numbers of everything you need, but apparently this place is more like a specialized hardware store and they encourage you to bring your parts and let their knowledgeable staff help. My friend says the fittings are around $1 each. I expect the check valve will be around $100, but I guess we'll see. After it's all said and done my rig will probably have cost around $400. I'm not sure it's much cheaper than if I had just bought a custom rig from someone. It's certainly cheaper than the dual stage from GLA. And it has every feature I wanted:


-dual stage regulator with stainless diaphragm


​​​​​​-Burkett solenoid with buna seal


-Fine metering valve with vernier handle


-Check valve
 

rajkm

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Check valve .. check eBay or go to a local Parker store. I get Parker check valves (brass) for less than $20.
 

i61164

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Apr 14, 2017
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I was under the impression that I needed a super expensive check valve, but I think you are right about cheaper options. I just reread the regulator build sticky and it seems there was an expensive custom check valve that Matt was using, but other ones were available at a fraction of the price. The important thing was for the check valve to have a 1/3 psig cracking pressure. And the expensive metal check valve was his backup. The first line of defense was a cheap plastic check valve from ADA. I couldn't find the page where he ordered it though because the links were broken. That will definitely keep my cost down.


I'm still undecided about the needle valve. I know Tom and others used a Parker H3L model that was available cheap on eBay several years ago. It costs hundreds of dollars now and might be overkill for this application. I'd get one in a heart beat if it was available for less than $100. Many builders seem to use the swagelok M series which has gotten mixed reviews and I've decided against that one. The swagelok S series is apparently a better option for low flow applications. Matt recommended either the Ideal valve or the Fabco and I've looked through the thread about the Ideal valves. I was pretty much decided on getting an Ideal valve (hopefully they are still available), but I noticed how cheap the Fabco is. It's about 1/3 of the cost and Matt installed them on several of his custom builds. Has anyone here used both or have an opinion on the Fabco vs the Ideal?
 

rajkm

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I have not used Fabco so not sure.


you need to look at the orifice and cv and stem degree. Anything with stem greater than 1 degree is bad at fine tuning.


there are few which are better than Swagelok S series.


Parker HR series HR0 ,HR1 may be HR2 is close. Parker NS series is close second.


Hoke micro mite. The hoke milli mite is close.


I have both the Swagelok S series, Hoke Micro Mite and a Swagelok S series double pattern.


the reference flow curve is important.


E.g with the hoke has 18 turns but only the first 8-10 turns give you best control, after that each turn increases the flow considerably.


http://www.hoke.com/pdf/Metering_Valves_Catalog_79013_10.12.pdf


The Swagelok S series has 10 turns and the first 5 turns give you best control


https://www.swagelok.com/downloads/webcatalogs/EN/MS-01-142.PDF


Same info for Parker HR series


https://www.valinonline.com/Userfiles/Documents/Parker-HR-Series-Metering-Valves.pdf


Link for Ideal valve


http://idealvalve.com/
 

i61164

Junior Poster
Apr 14, 2017
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Thanks again for all the info. I did some reading on old threads and found that the Fabco has a non-standard size which requires adapters to mount it to the regulator. And it also doesn't have the vernier handle although someone had a diy modification that was like a vernier. I'm sure it's a decent needle valve and a good value, but I'm probably going to go with the Ideal valve because it will be a cleaner installation onto the regulator and come with the vernier handle that I want. I'll probably call them tomorrow to confirm the price. People were getting them for less than $100 a few years ago which is a bargain. I've heard good things about both hoke and Parker valves, but from what I have seen they are going to be more expensive. It seems that the Ideal valve is widely regarded as very good and economical. Do you think the difference in 5 turns of the swagelok s vs. 8 turns of the hoke makes much difference? Obviously the hoke is a better or more precise valve, but does that extra precision matter? Can you accomplish your goals just as well with the Swagelok S or is it substantially more difficult to use?
 

i61164

Junior Poster
Apr 14, 2017
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I've got a small tank too. 26 gallons and a 10 gallon sump. Of course I realize that turns matter, but there is probably some diminishing returns at some point. I guess the tough question is "how many turns are enough?" In any case, I just got off the phone with Bill and ordered a brass Ideal valve V52-1-12. $98 shipped to anywhere in North America. He seemed like a really nice guy. I'm excited to be moving forward with my build.