CaRx Carbon Doser output setting not accurate?

[Rst]

The Carbon Doser is set at 1 bubble every 5 seconds which should produce 12 bubbles per minute.

Instead the bubble counter produces a little over 18 bubbles per minute as per the stopwatch.

I am following the member @jda CaRx's tuning advice, so I am adjusting the flow rate and bubble count as recommended.

My CO2 tank low pressure gauge is set @ 7.5 1bs feeding a Carbon Doser V1. The CO2 tank is completely full and has no leaks. I have purposely set the CO2 tank's pressure on the lower side in order to avoid really large bubbles. I have also installed the Carbon Doser's included back flow preventer.

Do other users experience the same level of inaccuracy. What causes this device to have such a large discrepancy?

 

[X-37B]

To be sure that you understand the outputs we are at, I am 15 bubbles every 400 minutes.


I am using this, and my suggestion is to use one. I just recomend not using a continous duty.

Remember not everyone has the money (or time and desire) for the size of tank that you have.

Ok I get it now. Had to look up your system. If it was my system I would just dose 2 part by hand. I do this on my 45 total 60g frag system and my nano cube.
I have dosed the frag system once a day by hand for over 2 years now. I have a carx system ready but just dont see the need at least not yet.
I only dose 14ml a day of esv.

 

[Rst]

To be sure that you understand the outputs we are at, I am 15 bubbles every 400 minutes.


I am using this, and my suggestion is to use one. I just recomend not using a continous duty.

Remember not everyone has the money (or time and desire) for the size of tank that you have.

Hi, we last chatted 2 weeks ago and I have since been trying to implement your CaRx method for low demand systems on my newly setup 35 gallon tank. I do have 2 CaRx currently, one on my main 150gal display tank (which is NOT a low demand tank) and the second on this newly setup 35gal tank (which eventually be a low demand tank).

So in order to get started and get some experience with your method, I am starting with the control of the bubbles broken down into 4 doses per day. Please remember that the following is just an experiment until I understand what are the needs of this low demand system.

Since this is a brand new setup, I have no idea of just how low to set the bubbles to, so I arbitrarily am trying to dose a fixed number of bubbles somewhere around 5 bubbles for 1secs every 6 hours (20 bubbles/day). I arbitrarily chose 5 bubbles here since I can't really count more bubbles than this in just one second. Herein the bubble control, became a major challenge.

If I am not mistaken, my CO2 bubble setting on my regulator seems to need a more open needle valve setting as you move from one ON/OFF cycle to the next ON/OFF cycle while still maintaining the ON cycle to running for 1 second. For example, if I start the cycles and turn ON the bubbles ON for 1 second I get 5 bubbles at a certain needle valve setting, then after the first 6 hours cycle with the bubbles OFF, the CO2 needle valve now requires to be rotated further open another 1/2 turn to reach the same 5 bubbles in 1 second. (No bubbles come out unless I open the needle valve more open). Then after 1 more 6 hour cycle again, I now need to rotate the needle valve another 1/2 turn to keep the same 5 bubbles in 1 seconds as before.

After many more of running 6 hour cycles, it seems that the needle valve needs constant increasing with every passing of another 6 hour cycle. Obviously with my system running like this, there would be no way to keep control of the bubbles output over time. For your information, my CO2 regulator on this tank is a Tunze German made 2 stage regulator with a built in needle valve.

 

[HuduVudu]

I arbitrarily chose 5 bubbles here since I can't really count more bubbles than this in just one second

It doesn't matter how many bubbles happen in the one second. What is happening is that the soleniod turns on for one second and pressurizes the line. This will provide bubbles even when the soleniod closes. For me I see about 3 bubbles in the first second and then there will be about 9 more bubbles over the course of about 15 seconds and then maybe I will get one more over 15 more seconds and by then it has exhausted the pressure and there are no more. So this gives about 12-13 bubbles all totaled. So if you are running a six hour off cycle then that is 360 minutes. Then that will be 12/360 bubbles per minute or 0.03 bubbles per minute. If you had a flucuation and got double the amount of bubbles (24) then that would be 0.06 bubbles per minute. This is a VERY small flucuation. This is why I don't worry so much about getting the exact bubble count.

I think that you are getting lost in the precision of the thing. This is one really important lesson that people struggle with in salt water aquariums. You want solutions that don't require insane precision. We are dealing with biological processes and they are inherently imprecise. I went away from 2 part dosing becuase the needed precision for the technique is a problem. Smaller tanks amplify that imprecision and make IMO two part impractical.

Just remember the final dictator for a CaRx is the dKH of the effluent. It should be around 25dKH. Mine runs very consistently at 22dKH. Having the dKH of the effluent stable is what gives you the power to move the effluent flow around to achieve the desired parameters in your tank.

For your information, my CO2 regulator on this tank is a Tunze German made 2 stage regulator with a built in needle valve.

I run the same regulator.

 

[Rst]

It doesn't matter how many bubbles happen in the one second. What is happening is that the soleniod turns on for one second and pressurizes the line. This will provide bubbles even when the soleniod closes. For me I see about 3 bubbles in the first second and then there will be about 9 more bubbles over the course of about 15 seconds and then maybe I will get one more over 15 more seconds and by then it has exhausted the pressure and there are no more.

I am wondering how you would recommend setting your bubbles in light of no bubbles appearing in the first second due to time for the pressure to build up before bubbles will be produced. Does this mean that I should set my time ON to be much greater than 1 second, maybe 15-30secs? Wouldn't this allow way too many bubbles at one time, which in turn would likely cause the effluent dkh to get much higher than the target of 25dkh?

In your case, when you have 15 bubbles every 400 minutes, how long do you keep the solenoid ON for and how many lbs of the 2nd stage pressure is your CO2 tank?

Just remember the final dictator for a CaRx is the dKH of the effluent. It should be around 25dKH. Mine runs very consistently at 22dKH. Having the dKH of the effluent stable is what gives you the power to move the effluent flow around to achieve the desired parameters in your tank.


I run the same regulator.

I do understand that the important paramater is keeping the effluent around 25dkh stable. But surely you still need some stability in the bubbles produced on a daily basis.

 

[HuduVudu]

I am wondering how you would recommend setting your bubbles in light of no bubbles appearing in the first second due to time for the pressure to build up before bubbles will be produced. Does this mean that I should set my time ON to be much greater than 1 second, maybe 15-30secs? Wouldn't this allow way too many bubbles at one time, which in turn would likely cause the effluent dkh to get much higher than the target of 25dkh?

Remember it is the combination of the flow rate AND the bubble count that will determine the effluent alkalinity.

The important thing for the CO2 side is the number of bubbles over time. If you need to leave the soleniod on for more than one second then that is fine. You just need to be able to get some number of bubbles. So if leaving the soleniod open for 2 secs gives you bubbles then that is what you need. Also the soleniod gives you the power over the time and not the bubbles. That works because you just need to get consistent bubbles. You could leave the soleniod on for a long time and then turn it off for even longer. It is the ratio for the bubbles that matters.

In your case, when you have 15 bubbles every 400 minutes, how long do you keep the solenoid ON for and how many lbs of the 2nd stage pressure is your CO2 tank?

I keep the soleniod on for 1 second, which is the minimum for my controller.

I was lucky and got a 20lb cylinder because they were out of the 10 pound ones when I was trying to fill and they upgraded me. My gawd, I really don't need it but I have it. My second stage is running 0.5 bar (7.2 psi)

I do understand that the important paramater is keeping the effluent around 25dkh stable. But surely you still need some stability in the bubbles produced on a daily basis.

Empiricaly I have found that this isn't really true. There seems to be a lot of lee way in your adjustments to get the correct dKH. You can overdo it but you will see that in the CO2 build up in the reactor. In my case (Korallin) the top of the chamber will have a big bubble. If I put too much CO2 into the reactor then I end up having to bleed off the bubble.

Also once you get the right ratio set up then moving the effluent flow is super easy and you don't have to re-adjust the pressure, just change the off time for the soleniod with the right ratio for the flow.

I hope that this is helping. It seems a lot more complicated than it really is IRL.

 

[Rst]

Remember it is the combination of the flow rate AND the bubble count that will determine the effluent alkalinity.

Agreed, its just that the Flow is so much simpler to set where ever you want. Its the bubbles that cause the difficulty. I will keep working on bubbles until I get a similar quantity each day and still keep the effluent @25dkh.

Also once you get the right ratio set up then moving the effluent flow is super easy and you don't have to re-adjust the pressure, just change the off time for the solenoid with the right ratio for the flow.

Understood.

I hope that this is helping. It seems a lot more complicated than it really is IRL.

Once again thanks for taking the time to explain. Really very helpful.

Ron

 

[HuduVudu]

Agreed, its just that the Flow is so much simpler to set where ever you want.

Yup, I found that to. That is why I went to the soleniod to try and get control of the bubble ratio.

Its the bubbles that cause the difficulty. I will keep working on bubbles until I get a similar quantity each day and still keep the effluent @25dkh.

Ok. Let me explain how I exactly did this.

First I just set up a flow rate. I set it kind of low. 320ml/day. It doesn't matter what the flow is, any flow will do. Then I hooked up the CO2 to the CaRx without a soleniod. I adjusted the bubble count to something like 8 bubbles a second. It doesn't need to be exact. What I was looking for on this step was to get something that wouldn't change over time. What I found is that if I went for a lower bubble count then for some reason (I think the needle valve) the bubble count would drift down and then stop. I am still dealing with effects of this event. So I wanted something that was high that I knew wouldn't change and it turns out that the bubble count was pretty high. This is the part that I think that you are having a hard time with. What the bubble count at this point is doesn't matter. I think you are trying to relate it forward into how many bubbles will happen in a second. As you have seen the on off function of the soleniod will not give exact bubble counts during the time that it is on. In my situation my open bubble count is 8 per second but when I put the solenoid on, I get 3 for the first second and then it is the pressure that pushes out the rest. There is no translation across when you do this. Fortunately there doesn't need to be. Once I had a stablish bubble count that I knew I could count on then I put on the soleniod. I guessed that one second would be a good solenoid on time so I did that. It gave me the 12ish bubbles. It was pretty consistent. I was turning on the soleniod every five minutes or so for one second, so that I could see how many bubbles that I was getting and that it was fairly consistent. I saw that it was giving me consistent bubble counts. I moved the off time from 5 minutes to I think 60 minutes and left it overnight to see what would happen. The next day I brought the off time back down to 5 minutes to see if it was stable ... it was. I was still getting 12 bubbles. Of course I had a huge CO2 bubble at the top of the CaRx so I drained that off and then pushed the off time up to 120 minutes. During this time I WAS NOT checking the effluent alkalinity. I just kept changing the off time until I didn't get a bubble at the top of the CaRx. Once I got that. I checked the effluent alkalinity. It was shockingly at 22dKH. I called it good enough for government work. This gave me the golden ratio. Then I checked the tank alk. It was a little low. I pushed the flow up a little bit and changed the off time for the soleniod. This kept my ratio. I had my tank at 8.2dKH.

This is a nice story but unhappily I found out about the bubble drift. I wasn't looking to see if I was still getting bubbles because the off time was at 4 hours and I wasn't going to wait and try to time and see when the soleniod came on. Needless to say the bubbles stopped. Then the CaRx wasn't producing my Ca went down and the alk went down. Then ugliness in trying to deal with that situation because in trying to fix the problem I started jacking the parameters around. LOL I learned very interesting things in this time. I haven't lost anything but my coral are definitely struggling.

 

[Rst]

What I found is that if I went for a lower bubble count then for some reason (I think the needle valve) the bubble count would drift down and then stop. I am still dealing with effects of this event.

Exactly the problem. The drifting of the bubble count! Even if you finally got a stabilized bubble count high enough to be consistent, it doesn't mean that it will hold. It might work initially, but then at some time (as you discovered), it just eventually goes down to zero. And like you saw, unless you keep an eye on it daily, trouble becomes inevitable.

So I wonder what you can do to avoid this? The only solution I can think of is either monitor your bubble count at least once or twice a day or alternatively you might be able to use your pH probe to automatically signal trouble if you pH goes out of the normal range other than when the bubbles are working as you expect? Of course this assumes you have a pH controller (like an Apex) to signal you when the pH is out of range.

As you have seen the on off function of the soleniod will not give exact bubble counts during the time that it is on. In my situation my open bubble count is 8 per second but when I put the solenoid on, I get 3 for the first second and then it is the pressure that pushes out the rest.

Strange that you can get bubbles out after the 1 second point. You would think that a closed solenoid can't let any pressure escape to push more bubbles through.

I put on the solenoid. I guessed that one second would be a good solenoid on time so I did that. It gave me the 12ish bubbles. It was pretty consistent.

in my case, testing every 5mins OFF and 1 second ON also produced a consistent number of bubbles. But when I moved to 6 hours OFF and 1 second ON, no bubbles came out unless I opened up the needle valve more than 6 hours previous.

This is a nice story but unhappily I found out about the bubble drift. I wasn't looking to see if I was still getting bubbles because the off time was at 4 hours and I wasn't going to wait and try to time and see when the soleniod came on. Needless to say the bubbles stopped.

If you already happen to have an Apex, maybe my pH controller idea might save this from happening in the future?

I haven't lost anything but my coral are definitely struggling.

Glad you haven't lost any corals. I also have lots of experience with dkh quickly going way too high or way too low. Mistakes come easy to me. Luckily I also managed not to lose any corals.

Ron

 

[HuduVudu]

Exactly the problem. The drifting of the bubble count! Even if you finally got a stabilized bubble count high enough to be consistent, it doesn't mean that it will hold. It might work initially, but then at some time (as you discovered), it just eventually goes down to zero. And like you saw, unless you keep an eye on it daily, trouble becomes inevitable.

So I wonder what you can do to avoid this? The only solution I can think of is either monitor your bubble count at least once or twice a day or alternatively you might be able to use your pH probe to automatically signal trouble if you pH goes out of the normal range other than when the bubbles are working as you expect? Of course this assumes you have a pH controller (like an Apex) to signal you when the pH is out of range.

It has been six months ish. Still have a consistent count.

Strange that you can get bubbles out after the 1 second point. You would think that a closed solenoid can't let any pressure escape to push more bubbles through.

Pressure build up in the line.

in my case, testing every 5mins OFF and 1 second ON also produced a consistent number of bubbles. But when I moved to 6 hours OFF and 1 second ON, no bubbles came out unless I opened up the needle valve more than 6 hours previous.

HERE IT IS!!!!

You are losing CO2. There are two possible reasons. One, there is a leak in the line somewhere probably at the connections. Two, you have used the wrong type of tubing to connect your stuff.

How to correct. I would use a soap and water mix to test all of the connections. If you don't find the leak then you have to assume that it is the tubing. There is special tubing that you have to use when you use CO2. I am not sure what it is called but I am sure some quick research will tease out the answer.

LOL, never even thought of this. Glad I am working with you on this because if I run into this I will know what it is.

Looking at this a little closer, this also could be your check valve being sticky or not having enough pressure to get opened. I changed mine out from the stock and got one that everyone recommends. If you want to know what it is .. I can get that. They are really cheap like 20 bucks. I have an extra because they were so cheap.

If you already happen to have an Apex, maybe my pH controller idea might save this from happening in the future?

Yah, a probe might have helped. Live and learn.

 

[Rst]

HERE IT IS!!!!

You are losing CO2. There are two possible reasons. One, there is a leak in the line somewhere probably at the connections. Two, you have used the wrong type of tubing to connect your stuff.

How to correct. I would use a soap and water mix to test all of the connections. If you don't find the leak then you have to assume that it is the tubing. There is special tubing that you have to use when you use CO2. I am not sure what it is called but I am sure some quick research will tease out the answer.

LOL, never even thought of this. Glad I am working with you on this because if I run into this I will know what it is.

Looking at this a little closer, this also could be your check valve being sticky or not having enough pressure to get opened. I changed mine out from the stock and got one that everyone recommends. If you want to know what it is .. I can get that. They are really cheap like 20 bucks. I have an extra because they were so cheap.

Yah, a probe might have helped. Live and learn.

Nice to know that once I find out what is causing the inconsistent bubble generation, I can look forward to success.

I will check for leaks at the connections and go from there. Never occurred to me that there may be a problem with a sticky check valve or a need to increase the pressure to open the check valve. If you happen to find a link to a better check valve, I will replace the one I have.

Ron

 

[Rst]

Thanks again to @HuduVudu, you found my problem. It was my home made bubble counter. (don't ask - I tried to copy the bubble counter that I have on my main CaRx [Korallin] and use this design on a non-Korallin CaRx). Big mistake. I exchanged this home made bubble counter for a standard stand alone bubble counter I have used in the past and made sure the connections were solid. It's not the greatest bubble counter, but at lease it doesn't leak. Bottom line is that your low demand system now works and still works when dosing every 6 hours. Now all I need to do is to tune the bubbles and flow rate to meet my tank's needs. Newly set up so I will be dosing with very long OFF times.

 

[HuduVudu]

Thanks again to @HuduVudu, you found my problem. It was my home made bubble counter. (don't ask - I tried to copy the bubble counter that I have on my main CaRx [Korallin] and use this design on a non-Korallin CaRx). Big mistake. I exchanged this home made bubble counter for a standard stand alone bubble counter I have used in the past and made sure the connections were solid. It's not the greatest bubble counter, but at lease it doesn't leak. Bottom line is that your low demand system now works and still works when dosing every 6 hours. Now all I need to do is to tune the bubbles and flow rate to meet my tank's needs. Newly set up so I will be dosing with very long OFF times.

Woot!!!

I am glad that you found the culprit. It is funny because small things always bite us in the behind. I am always thinking to myself the devil is in the details.