[Calmia22]

I have a Aquatek co2 regulator attached to a normal 5lb. co2 cylinder. I have had it running for a few weeks now, and everything was good.

Yesterday my fish were breathing heavily at the top of the tank. I have had the regulator on 2-3 bps. I turned it down and promptly did a 50% water change. Today I wake up to two platys dead, an otto, and my male angel just barely holding on. I completely turned the co2 off and I have had an air stone going in the tank all day. Happily my male angel is beginning to look better.

On the regulator however, I have the co2 turned down as low as I can, and I don't have the cylinder open much. In fact it's opened so little that it wasnt producing any co2 when I unplugged it. There has to be a better way to manage this, and to prevent my fish from getting sick.

Any advice on this?

 

[Kathyy]

Aquatek is a single stage regulator, right? When the tank is nearly empty and has only gas with no liquid CO2 left there is often an 'end of tank dump' that occurs with this type of regulator and the bubble count will increase dramatically. If you have been using the gas for a couple weeks and are only putting a couple bubbles per second in then either you have a leak somewhere or that isn't the problem.

Remember oxygen is critical to good fish health. Make sure there is a good ripple on the surface all the time. Did the amount of ripple change?

If the bubble count hasn't changed then perhaps something else in your system has. I know one time I burped the drain to the sump which made the surface of the sump very quiet reducing the CO2 that diffused out. The fish reacted within 5 minutes of that burp and I lost a number of fish.

 

[Darkblade48]

Some things I would like to point out:

The CO2 cylinder main valve should be open all the way; the regulator will regulate the pressure of the gas coming out.

What is your delivery pressure set at?

Is your CO2 cylinder nearing empty? If not, then EOTD as mentioned by Kathyy is not a likely culprit.

I also do not think you have a leak, since it would not explain how your fish were overgassed.

Instead, it may be just that someone bumped the needle valve (perhaps while doing maintenance on the aquarium)?

 

[fusiongt]

I use Aquatek as well. The first one I got ended up being faulty - I didn't realize this until a few weeks in. Double check yours to see if your bubble counter works when the solenoid isn't plugged in (ie: it's ON all the time no matter if you have it plugged in or not).

Mine was faulty and my LFS took it back and I got a new one that worked well (made sure to test it in store).

To test, I disconnect it from the main tank and just have the tubing go to a glass of water and see if it works when it's not connected.

That's one problem, but even if it's on 24/7 it shouldn't be so strong that it's suffocating the fish. If this is the case, there's too much cO2 coming out.

I would also double check to make sure there are no leaks on your Aquatek. Put on plumbers tape around your cO2 tank nozzle as well.


The person saying the actual cO2 tank should be open all the way, I don't think it has to be completely open. More than a "bit open" to half way open works for me. That's just my opinion but most LFS I've been to in the bay area say the same thing that it doesn't have to be all the way open.

 

[Darkblade48]

I would also double check to make sure there are no leaks on your Aquatek. Put on plumbers tape around your cO2 tank nozzle as well.

The connection between the CO2 cylinder and the regulator does not require teflon tape.

The nylon washer forms a tight seal between the two.

The person saying the actual cO2 tank should be open all the way, I don't think it has to be completely open. More than a "bit open" to half way open works for me. That's just my opinion but most LFS I've been to in the bay area say the same thing that it doesn't have to be all the way open.

True; the valve does not need to be open all the way, as pressure is not determined by how far the valve is open.

However, opening it too little can result in problems. I usually recommend opening it all the way, and then closing it back down about 1/4 to 1/2 a turn so that in case you need to close the cylinder valve quickly (and in a panic, turn the knob the wrong way), the knob does not get jammed.

 

[DarkCobra]

When I first got my CO2 cylinder, I asked a welder about how far to open the valve. He explained that there's three seals in a gas cylinder valve.

The first prevents gas from leaking out from the outlet when the valve is closed. Just like you'd find in a water faucet.

The second prevents gas from leaking out around the valve shaft when it's partially open. However, it's a bit difficult to get a tight seal around a rotating shaft against 800psi of pressure, without making the valve difficult to turn; so this one doesn't always work perfectly.

The third blocks leakage around the shaft without fail, regardless of whether the second seal is perfect; but only if the valve is fully opened. So while it's usually not necessary to fully open the value, it is good practice to do so until you feel the tension from that seal engaging.

Just wanted to elaborate on that, though it's probably no help to the OP.

 

[Calmia22]

Sorry I haven't replied. The pressure on the tank is around 1000psi, and it's operating at 45 psi so I don't think the tank is out. I have a in-tank bubble counter (the bubble counter/diffuser combo) and once the solenoid shuts the co2 off, it doesn't come back on or stay on. My fish got more active with the co2 at first, but now I have lost both of my angels, as well as countless other platies, and ottos. Can the co2 do permanent harm to the water? I have not had the co2 on since I first noticed issues, and I did a 50% water change but I still continue to loose fish. My remaining platies are not active at all. The bn pleco and cories however act as if nothing is wrong.

 

[switch26]

Co2 lowers the PH of your tank, so the more that is put into the tank the less oxygen that is in the tank.

Just need better water flow, i have an eheim that gives surface agitation and I also have a aqueon powerhead that i can position anywhere in my tank and that blows all the time.

I would also get a drop checker possibly if you can't tell.

 

[Nunster]

What happends to the human's lungs in this case? I am not sure, that's why I am asking. =) I would think there would be major damage to the lungs or something if we breathed in nothing but CO2. If not just brain damage? Are you sure your bottle is at 1000psi? I get mine at 800psi is why I am wondering. Personally I don't like having my 10lb bottle inside and why it is outside. Anything in the manifold/valve assembly goes wrong it will be leaked outside instead of co2 while I am sleeping.
Then having the valve wide open I second that. Keep it wide open to seal against that special seal in the tank valve or you can be leaking co2 straight into your home.
Then aren't you so post to run air stones in the aquarium at night while the co2 is off so the plants can absorb oxygen at night?

 

[kevmo911]

If CO2 hasn't been on, and fish are still dying, then CO2 isn't the problem. Check ammonia/nitrite levels first of all. Do a few 50% water changes. And look for issues in individual fish. Once you remove CO2 from the equation, continued fish deaths are the result of disease or extremely poor water parameters.

As far as the cories not being affected goes, bottom feeders seem to have more robust immune systems than many other fish, so this isn't surprising.

 

[Darkblade48]

Can the co2 do permanent harm to the water? I have not had the co2 on since I first noticed issues, and I did a 50% water change but I still continue to loose fish. My remaining platies are not active at all. The bn pleco and cories however act as if nothing is wrong.

CO2 does not remain in the water for very long; I would say within 24 hours, even with minimal surface agitation, all the CO2 would have off gassed. It will not remain in the water after this time, and any effects you are seeing are likely a result of something else.

Co2 lowers the PH of your tank, so the more that is put into the tank the less oxygen that is in the tank.

Injecting CO2 will not reduce the amount of oxygen that is in the water.

What happends to the human's lungs in this case? I am not sure, that's why I am asking. =) I would think there would be major damage to the lungs or something if we breathed in nothing but CO2. If not just brain damage?

Tissue/organ damage will result from lack of oxygen (due to CO2 hindering oxygen binding to hemoglobin).

According to the CDC, immediately lethal levels of CO2 are achieved at 40,000 ppm.

http://www.cdc.gov/niosh/idlh/124389.html

Are you sure your bottle is at 1000psi? I get mine at 800psi is why I am wondering.

CO2 cylinder pressure can vary with temperature. A full cylinder can be anywhere from 800 - 1000 PSI.

Personally I don't like having my 10lb bottle inside and why it is outside. Anything in the manifold/valve assembly goes wrong it will be leaked outside instead of co2 while I am sleeping.
Then having the valve wide open I second that. Keep it wide open to seal against that special seal in the tank valve or you can be leaking co2 straight into your home.

Even if an entire 10 pound cylinder were to empty all at once within a few minutes, you would be OK (unless you live in an airtight room/house). In addition, I'm sure the sound of all that gas rushing out would wake you up, causing you to open windows/doors.

A slow leak over the course of several weeks will not make a discernible difference on your health.

Then aren't you so post to run air stones in the aquarium at night while the co2 is off so the plants can absorb oxygen at night?

There is no need to run air stones at night while the CO2 is off; while it is true plants will be consuming oxygen (as they are respirating), provided you have sufficient surface agitation from your filter, you will be fine.

 

[Calmia22]

I have very high ph out of the tap, and my ph with co2 only goes down to 6.6 I have done a water change as well as added a airstone to the tank that has been on non-stop since the issues started. Nitrite/ammonia reads at 0. Nitrate reads at 50ppm.

I re-checked the cylinder and it's at 1000psi.

My filtration consists of 2 Aquatop cf 500 filters. My tank is a 75 gallon and that gives me somewhere around 800gph turnover rate. (Taking into consideration factory rating with filtration added) I also have quite a bit of surface agitation. The spray bars face up, and do a good job of that. Now I don't have carbon in my filters. Could that be an issue with co2? I have heard you should not have carbon in planted tanks.

All fish that have died, before death were gasping for air despite what I have done to the tank.

 

[kevmo911]

Again, you're focused on CO2. Either you missed my last post, or ignored it. But I will say again: your issues are not CO2-related, based on the fact that long after you cut off CO2, fish were still dying.

Quarantine the sick fish, keep the CO2 off, and hope to stabilize.

 

[Darkblade48]

I have very high ph out of the tap, and my ph with co2 only goes down to 6.6 I have done a water change as well as added a airstone to the tank that has been on non-stop since the issues started. Nitrite/ammonia reads at 0. Nitrate reads at 50ppm.

This means your issues are not related to CO2, as already mentioned.

Now I don't have carbon in my filters. Could that be an issue with co2? I have heard you should not have carbon in planted tanks.

No; having carbon in your filter or not has nothing to do with carbon dioxide.

Again, you're focused on CO2. Either you missed my last post, or ignored it. But I will say again: your issues are not CO2-related, based on the fact that long after you cut off CO2, fish were still dying.

Quarantine the sick fish, keep the CO2 off, and hope to stabilize.

+1.

 

[Hardstuff]

You gave NO mention of your Kh readings or Gh. You said your Ph is high out of tap. Now if your Kh turns out to be something like 6,7,or 8 you are in trouble. Your CO2 level will be somewhere around 48-64 ml/L of CO2 & you will gas your fish. If it turns out you have High Kh I would recommend cutting it down with some R/O water. you really need to know how hard your water is before injecting CO2. You should not drive the ph down that low IF you have hard water. A ph of 6.9 to 7.2 would be safer. Thats 1 of many problems with hard water. Now if you do not have hard water with high Kh then you need to look into other things like metal toxicity & disease like mentioned already, but my money is on high Kh & hard water . CO2 limits should not be higher than 40 mL/L in that range. My 2 cents.

 

[Hardstuff]

Nitrate levels of 50ppms is really, really, high & could be trouble for fish. I still feel the problem is a high concentration of CO2 because of high Kh. That being said running an air stone in a planted tank is defeating the purpose of even using CO2. You are just out gassing CO2 & driving your ph up. Now if its not a serious planted tank & maybe you are breeding shrimp, I could see MAYBE running an air stone or hospital tank, or running meds at high temp. Other than that a little surface agitation with all other elements in place should be a healthy well oxygenated system. I run an airstone when I mix R/O & tap when I make my water. It helps mix the water, but it is overkill. I mix R/O water 80% remineralized & 20% tap because my tap has high Kh. I have 7 Kh which is high for most planted tank applications. I lower it to a Kh of 4. Now I can drive my tank down to 6.6-6.8 & not worry about gassing. I could still gas but I would have to run 3 bubbles / second or more. I only run CO2 during photo period & I do not worry about ph swings. My dosage is about 2 bubbles per second using a diffuser on a 10 gallon tank with medium high light.

 

[kevmo911]

pH swings due to CO2 don't matter - this has been discussed at great length. KH is not an issue in the OP's case.

 

[Hardstuff]

I was not suggesting ph swings was the problem. With out knowing his Kh it is possible CO2 gassing is happening because of high Kh. He mentioned 6.6. That is low for high Kh. You did not get the main point of what I was saying. The ph swings was just a side comment. I do not worry about ph swings, what I do worry about is proper Kh & Gh.