Welcome to ScapeCrunch
We are ScapeCrunch, the place where planted aquarium hobbyists come to build relationships and support each other. When you're tired of doom scrolling, you've found your home here.
Social Feed
Staff member
I Donated 2026
Founding Member
This is an article written by @Zeus. that he generously posted here on ScapeCrunch. Thanks @Zeus.!
Why do we need a stable Carbon Dioxide (CO2) level?
A stable Carbon Dioxide (CO2) level or concentration is key to successfully growing plants in a CO2 injected tank. The CO2 concentration needs to be stable throughout the photoperiod, usually anything from 6 to 8 hours long, and consistent from one day to the next. If the CO2 level is not stable during this period, plants will have to constantly adapt and may not grow as well. A fluctuating CO2 concentration may also give algae an advantage and it could start to become a problem.
Stabilising CO2 during the photoperiod can be tricky and time consuming, and can sometimes take weeks of trial and error, especially for folk new to CO2 injection. Also key to success is good water flow. This is often overlooked but is essential to distribute CO2 evenly throughout the tank. CO2 travels 10,000 times slower in water than in air, so without good flow CO2 concentration will not be the same throughout the tank. Plants waving gently in the flow is a good indicator that it is adequate. Good surface agitation is also essential. This ensures adequate levels of gas exchange and helps to keep the tank water oxygenated.
What level of CO2 to aim for?
Many folk aim for a CO2 concentration of 30ppm. This is regarded as the upper safe limit for livestock. A lower CO2 concentration than 30ppm CO2 can also greatly benefit plants and is perhaps kinder to livestock, so don’t feel the need to hit the 30ppm mark. When tank water has 30ppm of CO2, the pH will be approximately 1.0 unit lower than it was before CO2 was injected. To find a tank’s CO2 level or baseline before injection starts, take a clean glass of tank water and leave it at room temp for 24 hrs after which take a pH reading. This will be the baseline or degassed pH of your tank water. For example, if the pH is 7.2 after fully degassing, and your target CO2 concentration is 30ppm then the target pH will be 6.2.
Watch your fish when Injecting CO2
It is best to adjust CO2 levels before adding any livestock to avoid accidentally stressing fish and other aquatic critters. If this is not possible it is essential to keep a close eye on your fish and shrimp etc when first injecting CO2 especially if you are new to the concept. Watch for any signs of abnormal behaviour. If the fish come to the surface and start gasping for air or show any other signs of distress, stop CO2 injection immediately. If this happens a large water change will be necessary as a temporary fix to reduce CO2 concentration and hopefully introduce more oxygen. Next check your equipment and don’t start CO2 injection again until you are confident the cause has been eliminated. If you are unable to get to the bottom of the problem seek advice or guidance, never be afraid to ask.
Injecting CO2
After starting to inject CO2 the pH of the tank water will drop quickly at first, then slowly until it reaches equilibrium with CO2 uptake by plants and CO2 loss from the water surface. If the injection rate is too high, you will overshoot your target CO2/pH which could be fatal to the tanks inhabitants so small steps at first are essential to avoid this. If the injection rate is too low, your tank water may take many hours to reach the target CO2 concentration and may not hold that concentration and remain stable once the lights come on. It’s often a case of trial and error, taking the greatest care to get it right especially when livestock is present.
Drop Checker (DC)
A drop Checker (DC) is a great tool for checking the concentration of CO2 in tank water. A working DC is filled with an indicator solution, usually a reagent in deionised water calibrated to a value of 4dkH. This solution changes colour according to the concentration of CO2. The colour will change from blue when tank water is fully degassed of CO2, to lime green when tank water has reached a CO2 concentration of 30ppm. DC’s can often change colour slowly; the rate varies with design and can take unto 2hrs. A DC can be used by itself to gauge CO2 concentration, however for the purposes of establishing a stable CO2 concentration it’s easier to use the combination of a pH profile and a DC
For further information on measurement using a drop checker, see Clive’s excellent article linked below
CO2 Measurement Using A Drop Checker
Time it takes to get your target CO2 level
The time it takes to reach a CO2 concentration of 30ppm varies with tank size and injection method. About 2hrs is normal for a 50 litre tank, but bigger tanks can take 4 to 5 hours plus.
Doing a pH profile
Doing a pH profile is a great way to achieve a stable CO2 concentration and is relatively simple to do, ‘if’ a little time consuming. Firstly, decide on your target CO2 level. Then find the baseline or degassed pH of your tank water as outlined above under the heading - What level of CO2 to aim for. Set the injection rate, or Bubbles Per Second (BPS) using a bubble counter, to a suitable level for your tanks size and CO2 setup. Take the pH of the tank water as CO2 injection starts or just before.
Thereafter, take a pH reading every 30 mins and note it down. As the pH change slows down start to take the pH a little more often. If the pH drops more than 1.0 unit reduce the injection rate (BPS). If it is taking too long to get the desired pH drop increase the BPS. Once the target pH is reached, turn the lights on, then keep taking the pH every 30 mins, repeating the BPS adjustment to keep the pH as stable as possible. After 4 to 5 hours of lights on turn the CO2 off and call it a day.
Next day take the pH as CO2 comes on and thereafter every 30 mins and note the time. As the target pH is reached turn the lights on and again note the time. Some fine tuning will probably still be needed to get a stable pH (I personally call it stable when there is less than 0.1 pH drift from lights on till CO2 off). So it’s a case of ‘rinse repeat’; check the pH and adjust BPS if required to suit, until you have a stable pH from lights on and all the way through to lights off. Then the hard work is over. DO NOT adjust your BPS rate again to try and get the pH to drop faster, it is not possible. The time it takes is the time it takes. You will have already got this time noted down. It may be 2hrs it may be 4 to 5hrs with bigger tanks. The length of time a pH drop takes is always worth a final check. You will already have a rough idea from the previous days pH profiling but some further fine tuning may be required.
The whole process can take days or even weeks to perfect, especially if you need to increase the water flow to ensure adequate CO2 distribution throughout the tank, or to increase surface agitation and therefore gas exchange. Other commitments, such as work and household chores, can interfere with the process so make sure you have at least a few days free to start with, any distraction may prove fatal to fish and other aquarium livestock, again another reason why it’s best to dial CO2 in before adding livestock.
If in doubt ask
Finally, there’s no such thing as a stupid question, especially where CO2 injection and the health of fish and other livestock is concerned. So if in doubt always ask. There are many experienced and knowledgeable members who will be only too happy to help.
@Zeus.
Dialing in the CO2 injection Rate and CO2 Profiles
Why do we need a stable Carbon Dioxide (CO2) level?
A stable Carbon Dioxide (CO2) level or concentration is key to successfully growing plants in a CO2 injected tank. The CO2 concentration needs to be stable throughout the photoperiod, usually anything from 6 to 8 hours long, and consistent from one day to the next. If the CO2 level is not stable during this period, plants will have to constantly adapt and may not grow as well. A fluctuating CO2 concentration may also give algae an advantage and it could start to become a problem.
Stabilising CO2 during the photoperiod can be tricky and time consuming, and can sometimes take weeks of trial and error, especially for folk new to CO2 injection. Also key to success is good water flow. This is often overlooked but is essential to distribute CO2 evenly throughout the tank. CO2 travels 10,000 times slower in water than in air, so without good flow CO2 concentration will not be the same throughout the tank. Plants waving gently in the flow is a good indicator that it is adequate. Good surface agitation is also essential. This ensures adequate levels of gas exchange and helps to keep the tank water oxygenated.
What level of CO2 to aim for?
Many folk aim for a CO2 concentration of 30ppm. This is regarded as the upper safe limit for livestock. A lower CO2 concentration than 30ppm CO2 can also greatly benefit plants and is perhaps kinder to livestock, so don’t feel the need to hit the 30ppm mark. When tank water has 30ppm of CO2, the pH will be approximately 1.0 unit lower than it was before CO2 was injected. To find a tank’s CO2 level or baseline before injection starts, take a clean glass of tank water and leave it at room temp for 24 hrs after which take a pH reading. This will be the baseline or degassed pH of your tank water. For example, if the pH is 7.2 after fully degassing, and your target CO2 concentration is 30ppm then the target pH will be 6.2.
Watch your fish when Injecting CO2
It is best to adjust CO2 levels before adding any livestock to avoid accidentally stressing fish and other aquatic critters. If this is not possible it is essential to keep a close eye on your fish and shrimp etc when first injecting CO2 especially if you are new to the concept. Watch for any signs of abnormal behaviour. If the fish come to the surface and start gasping for air or show any other signs of distress, stop CO2 injection immediately. If this happens a large water change will be necessary as a temporary fix to reduce CO2 concentration and hopefully introduce more oxygen. Next check your equipment and don’t start CO2 injection again until you are confident the cause has been eliminated. If you are unable to get to the bottom of the problem seek advice or guidance, never be afraid to ask.
Injecting CO2
After starting to inject CO2 the pH of the tank water will drop quickly at first, then slowly until it reaches equilibrium with CO2 uptake by plants and CO2 loss from the water surface. If the injection rate is too high, you will overshoot your target CO2/pH which could be fatal to the tanks inhabitants so small steps at first are essential to avoid this. If the injection rate is too low, your tank water may take many hours to reach the target CO2 concentration and may not hold that concentration and remain stable once the lights come on. It’s often a case of trial and error, taking the greatest care to get it right especially when livestock is present.
Drop Checker (DC)
A drop Checker (DC) is a great tool for checking the concentration of CO2 in tank water. A working DC is filled with an indicator solution, usually a reagent in deionised water calibrated to a value of 4dkH. This solution changes colour according to the concentration of CO2. The colour will change from blue when tank water is fully degassed of CO2, to lime green when tank water has reached a CO2 concentration of 30ppm. DC’s can often change colour slowly; the rate varies with design and can take unto 2hrs. A DC can be used by itself to gauge CO2 concentration, however for the purposes of establishing a stable CO2 concentration it’s easier to use the combination of a pH profile and a DC
For further information on measurement using a drop checker, see Clive’s excellent article linked below
CO2 Measurement Using A Drop Checker
Time it takes to get your target CO2 level
The time it takes to reach a CO2 concentration of 30ppm varies with tank size and injection method. About 2hrs is normal for a 50 litre tank, but bigger tanks can take 4 to 5 hours plus.
Doing a pH profile
Doing a pH profile is a great way to achieve a stable CO2 concentration and is relatively simple to do, ‘if’ a little time consuming. Firstly, decide on your target CO2 level. Then find the baseline or degassed pH of your tank water as outlined above under the heading - What level of CO2 to aim for. Set the injection rate, or Bubbles Per Second (BPS) using a bubble counter, to a suitable level for your tanks size and CO2 setup. Take the pH of the tank water as CO2 injection starts or just before.
Thereafter, take a pH reading every 30 mins and note it down. As the pH change slows down start to take the pH a little more often. If the pH drops more than 1.0 unit reduce the injection rate (BPS). If it is taking too long to get the desired pH drop increase the BPS. Once the target pH is reached, turn the lights on, then keep taking the pH every 30 mins, repeating the BPS adjustment to keep the pH as stable as possible. After 4 to 5 hours of lights on turn the CO2 off and call it a day.
Next day take the pH as CO2 comes on and thereafter every 30 mins and note the time. As the target pH is reached turn the lights on and again note the time. Some fine tuning will probably still be needed to get a stable pH (I personally call it stable when there is less than 0.1 pH drift from lights on till CO2 off). So it’s a case of ‘rinse repeat’; check the pH and adjust BPS if required to suit, until you have a stable pH from lights on and all the way through to lights off. Then the hard work is over. DO NOT adjust your BPS rate again to try and get the pH to drop faster, it is not possible. The time it takes is the time it takes. You will have already got this time noted down. It may be 2hrs it may be 4 to 5hrs with bigger tanks. The length of time a pH drop takes is always worth a final check. You will already have a rough idea from the previous days pH profiling but some further fine tuning may be required.
The whole process can take days or even weeks to perfect, especially if you need to increase the water flow to ensure adequate CO2 distribution throughout the tank, or to increase surface agitation and therefore gas exchange. Other commitments, such as work and household chores, can interfere with the process so make sure you have at least a few days free to start with, any distraction may prove fatal to fish and other aquarium livestock, again another reason why it’s best to dial CO2 in before adding livestock.
If in doubt ask
Finally, there’s no such thing as a stupid question, especially where CO2 injection and the health of fish and other livestock is concerned. So if in doubt always ask. There are many experienced and knowledgeable members who will be only too happy to help.
@Zeus.
0 Replies
·
825 views
Staff member
I Donated 2026
Founding Member
There is A LOT of history to this that is tied to some of the biggest names in the hobby's past. I tried to get them into the USA with Clause Christensen back in the 90s but no-go.
This would be big news for US hobbyists as availability of healthy, aquarium-ready plants is THE limiting factor in expanding the hobby in the USA.
11 Replies
·
79 views
Supporting
Journal Low and Slow
Finally a journal.
I’ll soon be setting up two new tanks, a UNS 90p and a 50c. (Not so!) Patiently awaiting tanks and stands delivery.
They will both be middle energy tanks. I have lengthy periods of busy time and travel that mean the tanks need to survive without human intervention here and there. So plenty of automation is needed, and slow and steady wins over high energy. Or in BBQ smoking terms: low and slow.
Plans:
My last tank has had a rough year. Hurricane Helene meant two weeks with no electricity, and much longer without decent water changes.
Then last summer the tank developed a slow leak while I was out of town (ugh!). Had to fly home for a week to triage. Fish and plants have been in temporary tanks. Plants are struggling. Photo is when they had already been in temporary bin for over 6 weeks, I was surprised it didn’t look like an algae infested swamp.
Sooo ready for my new tanks! These are my first really nice tanks, I’ve only owned petco specials before.
For the new tanks I'm planning on over ordering plants since my surviving plants are clearly pretty weak at this point.
I’ll soon be setting up two new tanks, a UNS 90p and a 50c. (Not so!) Patiently awaiting tanks and stands delivery.
They will both be middle energy tanks. I have lengthy periods of busy time and travel that mean the tanks need to survive without human intervention here and there. So plenty of automation is needed, and slow and steady wins over high energy. Or in BBQ smoking terms: low and slow.
Plans:
- Injected CO2, but less than 30ppm
- Inert gravel
- Tidal HOB filter and partial UGF plate.
- Less than EI ferts, but more than PPS pro.
- Tap water (my tap is 50 TDS and only 10ppm Ca) remineralized to 30ppm Ca and 3-4 dKH.
- Lower light levels: Week aqua L on 90p and Chihiros wrgb 2 slim on 50c.
- Easy slow growing plants, and a few fish. Thinking the 50c will be a shrimp tank.
- Some hardscape but nothing crazy
My last tank has had a rough year. Hurricane Helene meant two weeks with no electricity, and much longer without decent water changes.
Then last summer the tank developed a slow leak while I was out of town (ugh!). Had to fly home for a week to triage. Fish and plants have been in temporary tanks. Plants are struggling. Photo is when they had already been in temporary bin for over 6 weeks, I was surprised it didn’t look like an algae infested swamp.
Sooo ready for my new tanks! These are my first really nice tanks, I’ve only owned petco specials before.
For the new tanks I'm planning on over ordering plants since my surviving plants are clearly pretty weak at this point.
61 Replies
·
4850 views
Staff member
I Donated 2026
Founding Member
ADA has recently released the ADA Japan Denim Tool Pocket as a campaign-exclusive.
The pocket is made from denim fabric produced in Kurashiki, Okayama, one of Japan’s most renowned denim-producing regions. Handcrafted for both functionality and versatility, it provides a convenient way to organize and carry your aquarium maintenance tools, while also being designed for use in a variety of everyday situations.
If you are a gear-head like me, this is exciting news and I'm already trying to see how I can get my hands on this.
Filed under the heading, "Do I need it? No. Do I want it? Yes."
The pocket is made from denim fabric produced in Kurashiki, Okayama, one of Japan’s most renowned denim-producing regions. Handcrafted for both functionality and versatility, it provides a convenient way to organize and carry your aquarium maintenance tools, while also being designed for use in a variety of everyday situations.
If you are a gear-head like me, this is exciting news and I'm already trying to see how I can get my hands on this.
Filed under the heading, "Do I need it? No. Do I want it? Yes."
0 Replies
·
32 views
Staff member
I Donated 2026
Founding Member
The theme for this month's contest is: Algae Patina
This one is going to be tough but I hope some of you take up the challenge. There is a fine line between algae on an object that makes it look natural and old (patina) and algae on an object that simply makes it look unkept and dirty.
Who can strike that balance best??
Please take a picture of algae patina in your aquarium. Be as artistic and creative as you like.
The rules:
A $25 store credit from BurrAqua thanks to @Burr740!
Good luck!
This one is going to be tough but I hope some of you take up the challenge. There is a fine line between algae on an object that makes it look natural and old (patina) and algae on an object that simply makes it look unkept and dirty.
Who can strike that balance best??
Please take a picture of algae patina in your aquarium. Be as artistic and creative as you like.
The rules:
- Submissions are allowed between September 11 and September 23.
- Voting will start on September 23 at 12:01 am Eastern time.
- Voting will end on September 30 at 11:30 pm Eastern time.
A $25 store credit from BurrAqua thanks to @Burr740!
Good luck!
0 Replies
·
31 views
Supporting
I Donated 2026
AquaGirls
It will be tough to get away, but I have managed to finagle enough coverage for the weekend, so I did it! I have my ticket! I figure why not? It’s actually not that far from me. Daichi Araki from ADA is teaching an aquascaping masterclass on Saturday morning. Also interested in the ADA Shizuku workshop.
Juris Jutjajevs previously announced he will be attending the Jersey show.
I have never been to an Aquashella, so don’t entirely know what to expect, but I presume it is much like any large convention exhibit hall experience. Any ‘Crunchers thinking of attending the Jersey show?
Juris Jutjajevs previously announced he will be attending the Jersey show.
I have never been to an Aquashella, so don’t entirely know what to expect, but I presume it is much like any large convention exhibit hall experience. Any ‘Crunchers thinking of attending the Jersey show?
25 Replies
·
694 views
Staff member
I Donated 2026
Founding Member
Announcement August 2026 Media of the Month Contest Winner!
Please join me in congratulating @Jeff Miotke as the August 2026 Media of the Month winner!
This is the winning photo:
They win a $25 gift certificate from BurrAqua!
Congratulations for second place winner @Gwad and third place winner @CincyScaper!
This is the winning photo:
They win a $25 gift certificate from BurrAqua!
Congratulations for second place winner @Gwad and third place winner @CincyScaper!
0 Replies
·
22 views
Hello everybody,
I want to vacuum my complete soil and pull out all the plants add some apt root tabs en replant after.
Does anybody have tips or tricks to keep the shrimp safe during this big clean up.
I have a 350 liter tank 120x50x60. So thats quite a big surface.
The reason for the clean up is that my plants need to be replanted since i have not been doing maintenance for a few weeks and had some algae problems.
Since i need to pull out all the plants, a big vacuum would not hurt and will be easy.
Thanks in advance
I want to vacuum my complete soil and pull out all the plants add some apt root tabs en replant after.
Does anybody have tips or tricks to keep the shrimp safe during this big clean up.
I have a 350 liter tank 120x50x60. So thats quite a big surface.
The reason for the clean up is that my plants need to be replanted since i have not been doing maintenance for a few weeks and had some algae problems.
Since i need to pull out all the plants, a big vacuum would not hurt and will be easy.
Thanks in advance
6 Replies
·
216 views
This thread is for the general discussion of the link IFC Aquarium Fertilizer Calculator. Please add to the discussion here.
How to use: When opening the file everything should be self-explanatory. You will land on the 'Home' sheet. Follow from there. We highly suggest you read the quick Guide (a link is provided in the Home sheet when you open the file) so you understand the purpose of each of the sheets in the file. Once you have done that, and before you start playing the mad scientist, we suggest that you go through the CoreSetting sheet as it will allow you fine tune the backend to your specific situation/needs. This is not per-say a requirement and you can always do this anytime but it will allow you to get better acquainted with things. Once you have done that, you can go to the Tank&Dosing sheet. That's where you will start your journey in creating your fertilizer.
All sheets will have the following icons on the top left. Some will have less, some will have more depending on which sheet you are on.
These are simply shortcuts to other sheets for your convenience. However you can also go from one sheet to another using the traditional Excel tabs at the bottom of Excel as shown below.
Please read the following important technical notes:
@Zeus. & @Hanuman
How to use: When opening the file everything should be self-explanatory. You will land on the 'Home' sheet. Follow from there. We highly suggest you read the quick Guide (a link is provided in the Home sheet when you open the file) so you understand the purpose of each of the sheets in the file. Once you have done that, and before you start playing the mad scientist, we suggest that you go through the CoreSetting sheet as it will allow you fine tune the backend to your specific situation/needs. This is not per-say a requirement and you can always do this anytime but it will allow you to get better acquainted with things. Once you have done that, you can go to the Tank&Dosing sheet. That's where you will start your journey in creating your fertilizer.
All sheets will have the following icons on the top left. Some will have less, some will have more depending on which sheet you are on.
These are simply shortcuts to other sheets for your convenience. However you can also go from one sheet to another using the traditional Excel tabs at the bottom of Excel as shown below.
Please read the following important technical notes:
- The calculator is Excel-based and there is no MACRO/VBA involved. This was done on purpose to minimize any potential security risks.
- Compatible with Excel 365 for Windows and Mac. Should also work fine with Excel 2016 and Excel 2019. For Excel 2010 and 2013 our initial tests show it works fine but we did not fully test under those versions. In terms of visuals, things might also slightly differ from the intended look. Below those versions (i.e Excel 2007 or lower), the calculator will definitely not work as intended and we will not support if run under those versions).
- File will definitely not work as intended with free and open-source office suite like LibreOffice or under Linux and Co.
- Under Excel Online things don't look as intended. Some people report that calculations are fine but I never really took the time to fully debug it under Excel Online. Maybe one day I will.
- If you feel you screwed up something with the file or your Excel crashed unexpectedly it might be worth making a fresh download.
- Although the user has the option to select between metric and imperial units in the CoreSettings sheet, all user input NEEDS to be done in metric units. Why? Because the imperial units are only there to provide visual guidance.
- Finally, we provide the ability to chose between several currencies. However all prices currently in the calculator are expressed in British Pound sterling (GBP). If you want to change to another currency you will need to convert the prices yourself in the CoreSettings sheet where all the chemical compound prices can be updated at will.
@Zeus. & @Hanuman
5 Replies
·
1218 views
Supporting
I Donated 2026
Rockstar
Before taking up this hobby, I had a Creality 3D printer I used on rare occasions. I purchased it used and had problems with it from the start. It was supposed to be user friendly but that definitely wasn't my experience.
Once I put together my first scape and realized I could print some helpful parts and tools, I decided to purchase a new Bambu Labs A1 Mini. It opened my eyes to how easy and fun 3D printing could be. In the time since, I've been printing more and more items, not just for aquarium use, but stuff for projects all around the house. I decided it was time for an upgrade to something with a larger build volume. I was planning to move up to the A1 initially but then began thinking, perhaps having an enclosed printer might be smarter, to future proof my needs and desires going forward. After a lot of back-n-forth debating between the Bambu P2S and X2D, I ended up with the P2S this weekend. I have an expanding list of new aquarium related items I want to print
So what printers do others here use and what are your thoughts?
Once I put together my first scape and realized I could print some helpful parts and tools, I decided to purchase a new Bambu Labs A1 Mini. It opened my eyes to how easy and fun 3D printing could be. In the time since, I've been printing more and more items, not just for aquarium use, but stuff for projects all around the house. I decided it was time for an upgrade to something with a larger build volume. I was planning to move up to the A1 initially but then began thinking, perhaps having an enclosed printer might be smarter, to future proof my needs and desires going forward. After a lot of back-n-forth debating between the Bambu P2S and X2D, I ended up with the P2S this weekend. I have an expanding list of new aquarium related items I want to print
So what printers do others here use and what are your thoughts?
10 Replies
·
250 views
Staff member
I Donated 2026
Founding Member
Hello Welcome, faithnomore
Welcome to ScapeCrunch, @faithnomore!
We would love to get to know you. Please tell us about yourself. What tank do you have?
We would love to get to know you. Please tell us about yourself. What tank do you have?
3 Replies
·
66 views