• You are viewing the forum as a Guest, please login (you can use your Facebook, Twitter, Google or Microsoft account to login) or register using this link: Log in or Sign Up

150 ppm co2?

mrtank50

Member
Joined
6 Jan 2021
Messages
69
Location
Türkiye
Hello to everyone.
Friends, my tank is kh 4- gh-6
My pH is 5.8 although kh is high
Is this normal?

I think the CO2 is around 150 ppm.

There are no fish or other creatures in the aquarium.
There are only plants.

I've tested my testers many times and there's no margin for error.
Calibrations were done.

Is this situation harmful to plants?

Test kits:

Sera GH-KH
JBL GH-KH
Weipro Ph Controls and Adwa ph controls
 
Where are you getting the 150ppm figure from?

What is your PH before CO2 injection? It's very unlikely you have 150ppm CO2 but even if you did it would not harm your plants.
 
Get a drop checker to test your CO2 levels. That's inexpensive, easy and accurate. I would be very surprised if your CO2 really was at 150 ppm, and your plants don't need it to be that high. pH/kH charts are notoriously unreliable in real world settings. 30 ppm is usually presented as the level that gives good plant growth without harming livestock, although I prefer to push a little higher to 35-40 ppm.
 
Hey MrTank, you haven't updated your tank photos for a long time. Pls post photos of your Pantanal and L. Senegelansis! At 150ppm CO2 and a 6 x T5 lighting fixture, they are probably growing like weeds in your tank :)
 
Where are you getting the 150ppm figure from?

What is your PH before CO2 injection? It's very unlikely you have 150ppm CO2 but even if you did it would not harm your plants.
Kh-ph table

My ph dropped to 5.8 with the co2 on.

I turned off the CO2 for 12 hours.

After 12 hours my pH had risen to 7.3.
 
Is this situation harmful to plants?
Hi
It could be but it doesn't do any good. Plants don't need more than 30 ppm. And as for the measument, your 1.5 pH drop indicates 30 x more CO2 than equilibrium with atmosphere. Easy right? But what is the CO2 level in your room air we don't know. It can be anything between 400 ppm to 2500 ppm. This is 6 fold, and multiplied by 30 as per your water pH drop, and we get more confused.

So what doesn't lie? Drop checker. When you know it's solution dKH and you know what colour is the pH then you know the CO2 level. But keep in mind it is slow, it takes several hours to stabilize.
 
Hello everyone again. I waited exactly 24 hours.
pH 7.8 after 24 hours with CO2 off

With Co2 it dropped to 5.7. A full pH of 2.1 degrees.
 
Hi mrtank, you have made a very striking post!
I dont think I have ever read about anyone having such high concentrations of C02 in their home tank, most post are about folk struggling to achieve 30ppm.
I am guessing you have a close fitting tank lid ?
 
MrTank, you posted an earlier tank shot where you said the CO2 was 40-50ppm . Could you post an updated full tank shot - is there any difference in plant growth between 40-50ppm and 150ppm?
 
Plants don't need more than 30 ppm.
Plant will use as much CO2 there is available and as light requires/induces. Emersed plants are exposed to ambient 400ppm ++ of CO2 and they use it all-right. In greenhouse CO2 is injected to around 1000ppm sometimes more. Now obviously in an aquatic environment things are different and you wouldn't be able to inject so much CO2 before running into other issues.

So what doesn't lie? Drop checker. When you know it's solution dKH and you know what colour is the pH then you know the CO2 level. But keep in mind it is slow, it takes several hours to stabilize.
I disagree with this. As a starter because of the caveat your mentioned, but most importantly because depending where your place the DC you will have very different readings. So which DC is lying now? DCs don't technically tell you what the actual overall CO2 concentration in the water column is, but more the concentration of CO2 at that specific spot. If your CO2 distribution is not optimal (which is very often the case) and if you use a CO2 traditional diffusers (micro bubbles etc), I can tell you with a high degree of certainty that your CO2 will be very different from one spot to the other. To that, add the fact that we are reading a range of colors which is by far the least accurate thing. I personally only use a DC to know if there is or not CO2 in the tank and if there is no issue with my CO2 delivery, that's it. But not to know how much CO2 is present . It's best to use the PH drop method. So -1PH =~ 30ppm.
 
Last edited:
there is no rule that says you can only put 1 drop checker in a tank. I've seen photos of tanks with multiple drop checkers :)
LOL yeah you can put 50 if you want. Then it all comes down to aesthetics and if you are actually doing a pleasing looking aquascape or carrying out a mad scientist experiment. I suspect the first option is what the majority of people are most interested in though 😉 so the least hardware you have in your tank the better.
 
Thanks guys for your valuable reply.

When I opened this issue, I was aware that this situation was not normal.
But I was wondering what effects co2 might cause at very high values.

Damage to plants, damage to bacteria, etc.

This is a test tank.

I have 9 tanks, I chose one as a victim.

Estimated number of CO2 bubbles per second in test tank 10+

There are 2 separate CO2 solvents as diffuser + reactor.

But as far as I can see, the plants are suffocating and I can't get much yield. They started to lose their forms.

Even bacteria are slowly collapsing.
The tank is no longer as clean as it used to be.

Organic waste is increasing. I can't grow fertilizer.
There is a constant lack of micro and iron.
Beard algae and cyanobacteria began to appear.

I will add video and pictures as soon as possible.
 
For how long has this experiment been running for? What is the size of that tank? Are you using a PH pen or PH probe?

If you really have that much CO2 in that tank, the issue is not the CO2 per se but the O2 lacking thereof. Unless you are bringing O2 by more sophisticated means other than by simple surface agitation, it is not surprising that nothing is going good and dandy in that tank, hence bacteria dying, plants deforming etc. At those levels I would inject O2 the same way you inject CO2, meaning via pressurized means OR you have a large sump with some wet/dry trickle filters that will oxygenate water much more effectively.
 
Thank you for your valuable reply.

The tank has been running like this for 15 days.

Ph Probe available.

yes surface ripple
 
Plant will use as much CO2 there is available and as light requires/induces.
Research demonstrated that submerged plants do not need more than 30 ppm CO2 even under direct sunlight. Also, do you know anyone claiming the necessity of having 100 ppm of CO2 or facing issues related to too low CO2 at 30 ppm?
Emersed plants are exposed to ambient 400ppm ++ of CO2 and they use it all-right. In greenhouse CO2 is injected to around 1000ppm sometimes more.
Yes, that's how emersed plants work. In fact, terrestrial plants worldwide are starving for more carbon because of critically low atmospheric CO2 levels. We have ~ 400 ppm now thanks to burning fossil fuels for the last 120 years. It was as low as 300 ppm 120 years ago and it was like this for thousands of years, dropping down to critical level for plants to trive. The best time plants had it was when CO2 level in atmosphere was up to 8 000 ppm, 20 x more than today, it was millions of years ago. That's when ferns grew as large as trees. CO2 molecule is one of the most important molecules keeping this planet alive, CO2 is a molecule of life.
I disagree with this. As a starter because of the caveat your mentioned, but most importantly because depending where your place the DC you will have very different readings. So which DC is lying now?
Is pH probe positioning irrelevant?
DCs don't technically tell you what the actual overall CO2 concentration in the water column is, but more the concentration of CO2 at that specific spot.
Is pH probe any different? Does your pH probe technically read actual CO2 ppm? No, it doesn't neither.
It's best to use the PH drop method. So -1PH =~ 30ppm.
This is the least accurate method. The pH drop indicates how many times more CO2 is in the water sample in relationship to equilibrium with atmosphere. That's it, this is where it ends.

For the simple reason not knowing the atmospheric CO2 level at the testing site this process is not telling us what we want. Do you know what CO2 level is in your room air? I bet you don't. It can be anything between 400 and 2 500 ppm. The 400 is the average outside and the 2 500 has been tested in homes and malls. The 400 ppm CO2 infusion in water gives 0.5 ppm CO2 and the 2 500 gives significantly more. Now multiply this by your pH drop rate. In reality it can be anything. How accurate is it?
 
Research demonstrated that submerged plants do not need more than 30 ppm CO2 even under direct sunlight. Also, do you know anyone claiming the necessity of having 100 ppm of CO2 or facing issues related to too low CO2 at 30 ppm?
Please share such research. Always willing to learn more. Regardless, it's not about someone having the "necessity of" but rather if a plant can. You can grow plants at 30ppm, 20ppm, 10ppm heck even lower... that's exactly what happens in low tech tanks.
Is pH probe positioning irrelevant?
Technically no, but the PH of the water column of a tank tends to be more homogenous, so the reading of a PH probe will give you a better overall view of your tank compared to a DC which on top of this lags 2 to 3 hours.
Is pH probe any different? Does your pH probe technically read actual CO2 ppm? No, it doesn't neither.
See comment above.
This is the least accurate method. The pH drop indicates how many times more CO2 is in the water sample in relationship to equilibrium with atmosphere. That's it, this is where it ends.

For the simple reason not knowing the atmospheric CO2 level at the testing site this process is not telling us what we want. Do you know what CO2 level is in your room air? I bet you don't. It can be anything between 400 and 2 500 ppm. The 400 is the average outside and the 2 500 has been tested in homes and malls. The 400 ppm CO2 infusion in water gives 0.5 ppm CO2 and the 2 500 gives significantly more. Now multiply this by your pH drop rate. In reality it can be anything. How accurate is it?
Well unless you live in a factory, a mall or a cave, your CO2 level will be closer to 400ppm than the higher range. And to answer that question, yes I do have a CO2 detector which currently reads 458ppm :) - In the morning it read ~500 ppm give or take 5%. You're never too prudent when having a CO2 cylinder at home!
The pH drop indicates how many times more CO2 is in the water sample in relationship to equilibrium with atmosphere. That's it, this is where it ends.
Please elaborate on this. As much I know that a PH probe does not measure per say CO2 levels, it provides in my option a better approximation of what is in your tank. The -1PH ~ 30ppm is obviously an approximation, not a hard number. We all know that and live with that. I don't even understand what the equilibrium with atmospheric CO2 has to do here. We are forcefully dissolving CO2 at a much higher rate in a tank which is hardly the same thing as having 400-2500pm lingering in the air slowly dissolving in water. My PH would barely budge if I didn't inject any CO2.

In my opinion reading a DC's color is by far less accurate. But that's just me.
 
Well unless you live in a factory, a mall or a cave, your CO2 level will be closer to 400ppm than the higher range. And to answer that question, yes I do have a CO2 detector which currently reads 458ppm :) - In the morning it read ~500 ppm give or take 5%.
That's beatiful, I need one too!
Room CO2 levels vary a lot depending on the house structure and season. How the house is sealed and air conditioning or heating running. There are houses where CO2 was tested in the 2 500 ppm range.
Please elaborate on this. As much I know that a PH probe does not measure per say CO2 levels, it provides in my option a better approximation of what is in your tank. The -1PH ~ 30ppm is obviously an approximation, not a hard number. We all know that and live with that. I don't even understand what the equilibrium with atmospheric CO2 has to do here.
The whole idea of using pH probe as a proxy to get CO2 levels is based on differential pH between gassed and degassed water. And the only thing we know is that 1 pH => 10 x more CO2. But the problem is the degassed water doesn't have to be the same at different locations and timings. So let me ask you, where is the 1 pH drop getting the 30 ppm of CO2?

The princip doesn't have a solid starting point, no solid base. Most of us don't know the room air CO2 level so we cannot know what degassed CO2 ppm is. And even if we can test air CO2, we still don't know what it's equilibrium be. Then we go for 1 pH drop and we know we have 10 x more CO2 ppm than is in the degassed sample. But what is it? Is it 0.5, 5 or 10, we don't know. So how can we say 1 pH drop => 30 ppm, based on what?
 
The whole idea of using pH probe as a proxy to get CO2 levels is based on differential pH between gassed and degassed water. And the only thing we know is that 1 pH => 10 x more CO2. But the problem is the degassed water doesn't have to be the same at different locations and timings. So let me ask you, where is the 1 pH drop getting the 30 ppm of CO2?

The princip doesn't have a solid starting point, no solid base. Most of us don't know the room air CO2 level so we cannot know what degassed CO2 ppm is. And even if we can test air CO2, we still don't know what it's equilibrium be. Then we go for 1 pH drop and we know we have 10 x more CO2 ppm than is in the degassed sample. But what is it? Is it 0.5, 5 or 10, we don't know. So how can we say 1 pH drop => 30 ppm, based on what?
Agreed. Past observations and testing state that degassed water is somewhere arounf 3 to 4ppm so that's where the base line starts and the 1 PH drop equating to ~ 30ppm of CO2 is picked up. Your 400-2500ppm range is irrelevant in my opinion. We are not doing lab experimentation that require lots of accuracy. We are only interested in a way to dose CO2 to the point where it is not harmful to fish. The 30ppm could be 20ppm or 45ppm for all I care. What's more important is that everyone in the tank is healthy and plants grow and no algae proliferation is observed.

To me this is still better than using a simple DC for reasons I have already stated above.

Here are some link for those interested, which I assume you are already aware of:
 
Research demonstrated that submerged plants do not need more than 30 ppm CO2 even under direct sunlight. Also, do you know anyone claiming the necessity of having 100 ppm of CO2 or facing issues related to too low CO2 at 30 ppm?
Curious what research is this?

And yes I know plenty of people who's tank would be better if they optimized CO2 and had a higher concentration.

One issue is that many think their CO2 concentration is 30 ppm, but in reality they have no idea. It could more like 10 ppm. The charts are useless. There are more elements at play than just CO2 in our tanks.

And all of the theoretical nonsense aside for someone who is interested in having a great tank the pH drop method is easily the best method we have. If you know how to do it correctly it's our best available tool to dial in CO2 and keep it steady. That is unless you have access to very expensive test equipment.

IMO too many times folks get lost in the minutia and lose focus on what's important. Learn how to properly fully degas a sample, use a good calibrated probe, understand the dKH/pH/CO2 relationship, then take that knowledge to keep a steady pH drop and your odds of success will greatly increase.

So how can we say 1 pH drop => 30 ppm, based on what?
Now this I agree with. My pH drop is 1.4. What is my actual CO2 level? Who knows. The charts would say well over a hundred. Is it really? Not likely.

But matters little in the scheme of things. You want to dial in whatever level makes the plants the most happy and keeps livestock comfortable. Whatever that ppm is it pays to keep it steady at that level, and pH drop is the best tool to do so. Massive swings in CO2 are just as rough on some plants as massive swings in nutrients so it pays to get it right.
 
Back
Top