The Planted Aquarium Water Parameters – Environmental Indicators – Dissolved Carbon Dioxide

by Jun 20, 20208 comments

Every healthy ecosystem requires a balanced environment, including the environment we lived in. Just like we humans and land animals cannot survive breathing polluted air or drinking contaminated water, aquatic life (faunas and plants) will have a difficult time living in sub-optimal water. Of all the balanced factors that go into a successful planted aquarium – the filtration, lighting, CO2 injection, fertilization, substrate – I would insist that the quality of the water used in our planted aquariums may be the most important. In this article, we will be discussing all about planted aquarium water parameters.

Table of Contents

Importance of Knowing Good Water Parameters
Environmental Indicators
Dissolved Carbon Dioxide
Ways to Measure CO2 Levels in Our Planted Aquarium
Taking Advantage of the pH-KH-CO2 Levels Relationship Chart
A Caveat Within the pH-KH-CO2 Levels Relationship Chart
Drop Checkers
Observing Your Plants' Growth
Plants That Can Use Carbonates/Bicarbonates as Their Carbon Source
Too Much Dissolved CO2?
Providing Water Surface Agitation When Injecting CO2?
Stressing This Out Again
Conclusion
Closing Remarks

Weekly water parameters tests from the beginning weeks to months of your planted aquarium are critical to making sure that your parameters are in check, don’t let others say otherwise. The way co-hobbyists talk about good water parameters can be confusing at times. Add that to the fact that you may have different water sources and parameters due to your differing location/city, and you may not be able to replicate what works for him/her. That is why every planted aquarium is unique, and you have to find the balance of what you’ve got in hand.

Waterfall Nature

Waterfall Nature

Knowing what makes ‘good water’ for your planted aquarium is critical for maintaining a healthy environment for your fish and plants. It will help us understand the intricacies of a planted aquarium and will arm you with valuable insights on what to do if you notice any problems. Knowing good water parameters even helped me think outside the box, formulate theories, and tested it to see what works and what doesn’t, which I will explain later below.

The planted aquarium water parameters can be further broken down into categories, namely:

Nutrients

Ammonia/Ammonium

Nitrite

Nitrate

Phosphate

Minerals

Carbonates and Bicarbonates (KH)

Calcium and Magnesium (GH)

Environmental Indicators - You Are Here - Dissolved CO2

pH

Temperature

Dissolved Carbon Dioxide

Chlorine/Chloramine

TDS (Total Dissolved Solids)

After we discussed the Temperature part of determining good water parameters for our planted aquarium, we will now be discussing the Dissolved Carbon Dioxide part, what are its effects, what happens if you have too much or too low, what can you do if you have too much or too low, how to test, etc. We will also provide the acceptable water parameter ranges for different types of freshwater planted aquariums near the end of these articles.

Environmental Indicators

Dissolved Carbon Dioxide – The Primary Nutrient

As for all living things, Carbon (C) is essential, including our aquarium plants. The main source of Carbon for plants, whether terrestrial, semi-aquatic, or aquatic, is Carbon Dioxide (CO­2). Terrestrial and half-submerged plants usually absorb an adequate amount of CO2 from the air with their leaves. The average concentration of CO­2 in the air is currently 0.04 % (412 ppm) by volume.

However, things are totally different underwater. One of the main limiting factors for plant growth, in many natural bodies of water or our planted aquariums, is the low supply of CO­2. This is not because carbon dioxide has a low concentration in water than in air, but because gases dissolved in water diffuse at an incredibly slower rate than in the atmosphere (around 10,000 times slower). This means that our aquarium or submerged plants use the dissolved CO­2 10,000 times slower than terrestrial plants. This also applies to dissolved oxygen in the water.

This is one factor that makes it impossible for terrestrial plants to survive underwater for a lengthy time. Nonetheless, semi-aquatic and aquatic plants adapted to this environment and learned how to optimize their CO­intake.

Hardscape Diorama Style Aquascaped by Jordy Midel Jr. Philippines

Hardscape Diorama Style Aquascaped by Jordy Midel Jr. Philippines

Hardscape Diorama Style Aquascaped by Payat Aquino Hernandez Philippines

Hardscape Diorama Style Aquascaped by Payat Aquino Hernandez Philippines

As I mentioned before, carbon dioxide is naturally produced in our planted aquariums, even if you are not injecting CO2. When beneficial bacteria break down the wastes in our tank, and when faunas respire, CO2 is produced. While carbon dioxide accumulates during lights off, it will quickly be depleted by your plants at the start of lights on.

The equilibrium of CO2 inside our planted aquariums to the atmosphere is very low (2-3 ppm) compared to natural rivers or streams. Natural environments have much more elevated carbon dioxide levels (from 10-40 ppm) from the breakdown of organic wastes/matter, and primarily from soil and rocks respiration from underground (trapped carbon dioxide).

Gas Bubbles Carbon Dioxide Laacher Lake Germany

With that said, this is why all head springs have more dissolved carbon dioxide in them (we call them ‘bukal’ here in the Philippines), typically reaching 50 ppm + as depicted by the lush growth of vegetation from the source and diminished plant growths with distance as it flows far away from the source.

We will discuss in-depth the benefits of injecting CO2 into our planted aquariums in a future article, most especially on planted aquariums that have low to moderate lighting or the benefits that CO2 injection gives your plants even if you are keeping undemanding plants or low light plants.

Ways to Measure CO2 Levels In Our Planted Aquarium

While there are no commercial products (well there is, but it is slow to register and the margin of error is significant) or test devices available for us hobbyist to measure CO2 levels in our water, if there is any, it could only be available for scientific purposes or laboratories, out of reach, impractical and too expensive for a common hobbyist.

Nature Style 7 Gallons with CO2 Injection Aquascaped by Omar Krishnan Afuang Philippines – Please Observe how the CO2 Bubbles are distributed across the Whole Tank While Providing Water Surface Agitation

Taking Advantage of the pH-KH-CO2 Levels Relationships Chart

As I said in the previous article, when injecting CO2 in our planted aquariums, some CO2 reacts to the water molecules to form carbonic acid, which lowers the water’s pH.

It depends on the rate at which you are injecting CO2 (which depends on your lighting intensity), the injection method (misting via diffusers or 100 % dissolved via reactors), distribution, and how much CO2 is degassed whether you are providing surface water agitation or not.

CO2 levels can then be measured by comparing the pH level before CO2 injection and the pH level during peak saturation, a few couple hours from starting to inject CO2. During this time, pH will continuously and steadily drop until it reaches equilibrium. The rate of your CO2 injection equals the rate of off-gassing CO2 (off-gassing CO2 can be done by providing surface water agitation).

Using your API Freshwater Master Test Kit, you need 2 values, one, the pH level before you inject CO2, and two, the pH level at some point in time during CO2 injection (peak saturation point of dissolved CO2 in your water). Peak CO2 levels may take 1-3 hours of CO2 injection. In my case, it took 2-3 hours at 2 bps. So my CO2 is always scheduled to turn on 2 hours before lights on (you can scroll the table horizontally on mobile devices).

KH
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
pH
6.0
30
60
90
120
150
180
210
240
270
300
330
360
390
420
450
480
510
540
570
600
6.1
24
48
72
96
120
143
167
191
215
239
263
286
310
334
358
382
406
429
453
477
6.2
19
38
57
76
95
114
133
152
171
190
209
228
247
266
284
303
322
341
360
379
6.3
16
31
46
61
76
91
106
121
136
151
166
181
196
211
226
241
256
271
286
301
6.4
12
24
36
48
60
72
84
96
108
120
132
144
156
168
180
192
204
215
227
239
6.5
10
19
29
38
48
57
67
76
86
95
105
114
124
133
143
152
162
171
181
190
6.6
8
16
23
31
38
46
53
61
68
76
83
91
98
106
114
121
129
136
144
151
6.7
6
12
18
24
30
36
42
48
54
60
66
72
78
84
90
96
102
108
114
120
6.8
5
10
15
20
24
29
34
39
43
48
53
58
62
67
72
77
81
86
91
96
6.9
4
8
12
16
19
23
27
31
34
38
42
46
50
53
57
61
65
68
72
76
7.0
3
6
9
12
15
18
21
24
27
30
33
36
39
42
45
48
51
54
57
60
7.1
3
5
8
10
12
15
17
20
22
24
27
29
31
34
36
39
41
43
46
48
7.2
2
4
6
8
10
12
14
16
18
19
21
23
25
27
29
31
33
35
36
38
7.3
2
4
5
7
8
10
11
13
14
16
17
19
20
22
23
25
26
28
29
31
7.4
2
3
4
5
6
8
9
10
11
12
14
15
16
17
18
20
21
22
23
24
7.5
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
19
7.6
1
2
3
4
4
5
6
7
7
8
9
10
10
11
12
13
13
14
15
16
7.7
1
2
2
3
3
4
5
5
6
6
7
8
8
9
9
10
11
11
12
12
7.8
1
1
2
2
3
3
4
4
5
5
6
6
7
7
8
8
9
9
10
10
7.9
1
1
2
2
2
3
3
4
4
4
5
5
5
6
6
7
7
7
8
8
8.0
1
1
1
2
2
2
3
3
3
4
4
4
4
5
5
5
6
6
6
7

Most of the time, hobbyists aim for a full 1 pH drop, which will give you about 30 ppm level of CO2 give and take in your water column, according to the table. For example, if you have a KH of 3 dKH and started with 7.4 pH without CO2 injection, you would aim for a 1 pH drop, which is 6.4, during CO2 injection, which will give you about 30 ppm (not 36 ppm – I will explain later below) of CO2 level.

30 ppm of CO2 (1 pH drop) in a planted aquarium is the consensus for your plants’ optimum CO2 levels without harming our faunas. As a beginner, we wouldn’t recommend that you exceed this unless you have the experience and vigilance to monitor your faunas.

For example, I want optimal and controlled growth, and I don’t want to trim my plants every week, so I aim for just a .6 drop in pH. I have a KH of 3 dKH and started at 7.4 pH and ends with 6.8 pH after 2-3 hours of CO2 injection at 2 bubbles per second-rate. It will stay that way for the rest of the photoperiod even if I provide surface water agitation. This will give me approximately a CO2 level of around 15 ppm. That way, I just need an 80 % intensity on my light, less fertilization, less CO2 consumption from my pressurized tank, minimal (just some GSA in the glass every 2-3 days) to no visible algae, and less trimming. And I am not keeping any CO2 “very demanding” plants anyway.

My Plants Giving Off Oxygen

Tuning your CO2 bubbles per second-rate to yield a 1 pH drop within a couple of hours takes time and thorough planning from you. You must be present and be very vigilant in observing your faunas throughout the testing phase or photoperiod. You must learn how to properly distribute the CO2 across the whole tank and prolong contact with water before it off-gasses in the water surface.

Remember this. Plants can re-program their enzymes to whatever CO2 levels are available. It may take a week or two. Not only with CO2, but aquarium plants can also adapt to a wide range of lighting spectrum (I am not talking about intensity or PAR – we will get to that in the future article about lighting). They will grow just fine even with white light only, albeit you may not achieve those red, orange, violet pigmentation of plants you saw on other planted tanks that you certainly dreamed of. But did you know that not all red aquarium plants are a happy plant?

Aquarium plants can develop some irritation to very high light intensities, in which they will use some protection against it. That is why they turned red, pink, or orange other than green. Some plants also turn red due to deliberate nutrient limiting. While they really look mesmerizing and provide needed contrast of colors to the aquascape during the photo shoot, it doesn’t necessarily mean the plants are happy. We will discuss this in-depth in a future article.

Dutch Style Using DIY CO2 only Aquascaped by Aristotle Acha Philippines

Dutch Style Using DIY CO2 only Aquascaped by Aristotle Acha Philippines

A Caveat Within the pH-KH-CO2 Levels Relationships Chart

Always use two measurements, don’t gauge your CO2 levels, for example, using just one point in the chart. If, for example, you have a KH of 8 dkH and a pH of 7.0 without CO2 injection, the chart shows you already have a 24 ppm CO2 level, which is simply not true. Remember, I said above that the equilibrium level of CO2 in our tank compared to the atmosphere is quite low (2-3 ppm) without CO2 injection (Henry’s Gas Law).

Add this to the fact that there are a lot of chemical reactions within our planted aquarium that cause pH to drop besides injecting CO2.

With the example again above, you have a KH of 8 dKH and a pH of 7.0 without CO2 injection. The CO2 level in your tank should be in equilibrium with the atmosphere, and that should be around 2-3 ppm (called atmospheric equilibrium), not 24 ppm.

KH
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
pH
6.0
30
60
90
120
150
180
210
240
270
300
330
360
390
420
450
480
510
540
570
600
6.1
24
48
72
96
120
143
167
191
215
239
263
286
310
334
358
382
406
429
453
477
6.2
19
38
57
76
95
114
133
152
171
190
209
228
247
266
284
303
322
341
360
379
6.3
16
31
46
61
76
91
106
121
136
151
166
181
196
211
226
241
256
271
286
301
6.4
12
24
36
48
60
72
84
96
108
120
132
144
156
168
180
192
204
215
227
239
6.5
10
19
29
38
48
57
67
76
86
95
105
114
124
133
143
152
162
171
181
190
6.6
8
16
23
31
38
46
53
61
68
76
83
91
98
106
114
121
129
136
144
151
6.7
6
12
18
24
30
36
42
48
54
60
66
72
78
84
90
96
102
108
114
120
6.8
5
10
15
20
24
29
34
39
43
48
53
58
62
67
72
77
81
86
91
96
6.9
4
8
12
16
19
23
27
31
34
38
42
46
50
53
57
61
65
68
72
76
7.0
3
6
9
12
15
18
21
24
27
30
33
36
39
42
45
48
51
54
57
60
7.1
3
5
8
10
12
15
17
20
22
24
27
29
31
34
36
39
41
43
46
48
7.2
2
4
6
8
10
12
14
16
18
19
21
23
25
27
29
31
33
35
36
38
7.3
2
4
5
7
8
10
11
13
14
16
17
19
20
22
23
25
26
28
29
31
7.4
2
3
4
5
6
8
9
10
11
12
14
15
16
17
18
20
21
22
23
24
7.5
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
19
7.6
1
2
3
4
4
5
6
7
7
8
9
10
10
11
12
13
13
14
15
16
7.7
1
2
2
3
3
4
5
5
6
6
7
8
8
9
9
10
11
11
12
12
7.8
1
1
2
2
3
3
4
4
5
5
6
6
7
7
8
8
9
9
10
10
7.9
1
1
2
2
2
3
3
4
4
4
5
5
5
6
6
7
7
7
8
8
8.0
1
1
1
2
2
2
3
3
3
4
4
4
4
5
5
5
6
6
6
7

For the KH range of 1-10, always aim for a 1 pH drop regardless of your starting pH before CO2 injection (7.0 to 6.0 in the example above during peak saturation when injecting CO2), and that will give you about 30 ppm of CO2 level give and take (not 240 ppm).

Tuning your CO2 bubbles per second-rate to yield a 1 pH drop within a couple of hours takes time and thorough planning from you. You must be present and be very vigilant in observing your faunas throughout the testing phase or photoperiod. You must learn how to properly distribute the CO2 across the whole tank and prolong contact with water before it off-gasses in the water surface.

What about a KH range higher than 10? Well, it’s already in the territory of hard water in which more plant species will grow slowly or not at all. Cichlids tanks are within this tank parameter, and if you remember the Biotope for Cichlids in Malawi Lake, it is scarcely planted and lots of rocks. While you can still include plants, plants that can live among Cichlids are the undemanding and slow-growing types such as Anubias, injecting CO2 is a waste. Anubias will still grow slowly.

Plus, at very high KH levels, it will essentially soak up the CO2, binding/reacting into the CO2 molecules preventing the plants from using it (CO2), so CO2 injecting is a waste in a very hard water (high KH) tank.

Cichlids Tank

Drop Checkers

I will cut to the chase. I really don’t like to recommend drop checkers for beginners (I tried it before, actually, until I realized the drawbacks) due to the following reasons:

  • slow to register – what you actually see at that moment (the color) is the reading a couple of hours before. This means you might be a couple of hours behind only to find out that you are already in dangerous levels of CO2 for your faunas, which might still be wrong because:
My CO2 Drop Checker

This is just for illustration purposes what does a drop checker look like. I am not actually using my drop checker anymore.

  • The green or yellow color means that the drop checker happens to be in that spot (you put that drop checker in there, right?) and receiving CO2 bubbles. It doesn’t mean that you have optimal CO2 levels across the whole tank. That is why it is often suggested to put your drop checkers where the stream of CO2 bubbles goes to, opposite the outtake of your filter (to catch those bubbles), giving you a false reading and feeling of satisfaction and will most likely just out-gassed in the water surface. This false reading will hinder you from learning to distribute your CO2 across the whole tank properly, prolonging the CO2 bubbles contact with water before reaching the surface, and makes you wonder why are my CO2 demanding plants still not looking good?

These reasons alone make for a large margin of error when using drop checkers.

Hardscape Diorama Style 10 Days Old Aquascaped by Rowan Neal Lidres Philippines

Hardscape Diorama Style 10 Days Old Aquascaped by Rowan Neal Lidres Philippines No CO2 Injection

Observing Your Plants Growth

As you gain more experience tending for your planted aquarium, you will notice that some aquarium plants can be a good indicator if you have optimal CO2 levels or not in your aquarium.

This observation skill is not developed yet for new hobbyists. Still, as you grow different aquarium plants on different tanks with different setups, you will gain more experience and valuable insights on how to balance your lighting, CO2 injection, and fertilization schedule for your plants’ robust and optimal growth.

You should observe your plants’ reaction to CO2 injection for weeks or even months. It is also a good idea to do this during the cycling of your planted aquarium. No faunas yet. For more experienced hobbyists, you can bombard your plants (higher bps – no faunas yet) immediately after setting up your planted aquarium. There are still many unbalance factors on a newly setup planted aquarium, but you can give your plants a fighting chance by tuning your CO2 injection early. We don’t even recommend injecting CO2 for a beginners’ first aquascape. Learn the fundamentals first of keeping a planted aquarium, and then go from there.

My Rotala Respiring Oxygen

However, there are exceptions. And it all falls to just balancing all the factors.

I have no definite list of plants’ growth indications due to lack of CO2 because some of it may be attributed to other factors (lighting, fertilizers, water parameters, overall balance, etc.). For example, I’d seen from co-hobbyists who managed to grow lush carpets known to require CO2 injection using just regular potting or gardening soil topped with sand (no CO2 injection).

I’ve seen a Walstad tank from a friend who grows plants with no elongated nodes, no uneven growth patterns, no deformed or small leaves.

Walstad Tank No Filter Since Day 2 No CO2 Injection Aquascaped by Mark Ivan Suarez Philippines

Walstad Tank No Filter Since Day 2 No CO2 Injection Aquascaped by Mark Ivan Suarez Philippines

I’ve seen a lush tank with no CO2 injection, using just a DIY LED light and unconventional fertilization.

Dutch Style DIY Light No CO2 Dirtied and Using Banana Peel and Fish Gills as Fertilizer Aquascaped by Aristotle Acha Philippines

Dutch Style DIY Light No CO2 Dirtied and Using Banana Peel and Fish Gills as Fertilizer Aquascaped by Aristotle Acha Philippines

While the common thing with these tanks is that they use regular soil, which is known to release more CO2 due to organic decomposition, it is still not optimal, but the hobbyist managed to find the balance.

Remember, plants can adapt to what’s available to them. Even if one factor is not optimal, your CO2, for example (you don’t have to aim for a 1 pH drop), you should balance the other factors to avoid algae bloom.

Again, I want optimal and controlled growth with my current setup, and I don’t want to trim my plants every week, so I aim for just a .6 drop in pH. I have a KH of 3 dKH and started at 7.4 pH and ends with 6.8 pH after 2-3 hours of CO2 injection at 2 bubbles per second-rate. It will stay that way for the rest of the photoperiod even if I provide surface water agitation. This will give me approximately a CO2 level of around 15 ppm. It’s half-down from optimal. That way, I just need an 80 % intensity on my light, less fertilization, less CO2 consumption from my pressurized tank, minimal (just some GSA in the glass every 2-3 days) to no visible algae, less trimming, and my plants are still thriving. And I don’t want to mess with that balance by introducing very demanding plants.

Of course, if I used a shallow tank next time (my 35 gallons is 16″ tall), that is another effort to finding the balance.

Two Weeks Well and Controlled Growth No Trimming Yet

But did you know that some aquatic plant species can use hydrogenous carbonates/bicarbonates as their carbon source when the levels of CO2 are lacking (when not injecting CO2 or insufficient COinjection and you have hard water)? There is a visible sign of this called “biogenic decalcification,” where the calcium carbonate in lime CACOprecipitates on the leaves’ upper side and glass surfaces. This process is usually accompanied by some increase in pH in our planted aquariums, sometimes into lethal levels for our faunas.

This precipitated calcium carbonate looks greyish white, granular, and crumbly crusts are usually found in submerged plants in nature and aquarium plants like Vallisneria, Echinodorus, Najas species, Elodia species, Ceratophyllum, or Waterweeds.

With these groups of plant species, when it comes to competing with CO2, there are differences too. Waterweeds such as Eigeria Densa (Anacharis), Najas species, and Elodia species, in bright lighting, can take so much CO2 from bicarbonates that the pH can go up to 9 and 10, and that is dangerous to your faunas. Below them come the Vallisneria and Ceratophyllum. Third, are the larger Echinodorus. Usually, this is fixed by injecting a sufficient amount of CO2 in our planted aquariums.

I hadn’t witnessed this when I still had my Jungle Vals and when I was still using hard deep-well water since I am injecting CO2, but enough of this.

Too Much Dissolved CO2?

While you can bombard your plants with too much CO2 without any negative effects on them (if you are just keeping plants), except going on a frequent trip to your friendly CO2 refilling stations. Too much CO2 can kill your faunas, and that is independent of KH and pH.

Dutch Style Bombarding CO2 for Plants (no Faunas) Aquascaped by Dennis Sancio Philippines

Dutch Style Bombarding CO2 for Plants (no Faunas) Aquascaped by Dennis Sancio Philippines

While I’ve heard from other hobbyists that tried > 30 ppm levels (more than 1 pH relative drop – either deliberate or not) without harming their faunas (you should take that with a grain of salt, could be they are not telling the whole story), I’ve also heard of accidents from hobbyists that gassed their faunas due to faulty DIY CO2 setups or using cheap single-stage regulators.

Providing Water Surface Agitation When Injecting CO2?

It is crucial to provide water surface agitation even when injecting CO2. It might seem contradictory (degassing), but this is to allow oxygenation of the water, higher CO2 injection rates, and be able to reach peak CO2 saturation in a few hours and stay that way. But you must find the balance of how much water surface agitation you need to provide, with the rate of your CO2 injection (bubbles per second), your distribution methods, to prevent the CO2 levels from reaching dangerous levels and to achieve maximum saturation (1 pH drop) within 2-3 hours before lights on.

Oxygenating the water via surface agitation combined with cool waters we discussed in the last article means more oxygen for our faunas and plants during lights off. Oxygen and CO2 levels in our planted aquariums are independent of each other.

When I was tuning my CO2 injection, I used my aquarium fans and the outtake of my canister filter (pointed towards the surface of the water) to provide water surface agitation.

I am using a CO2Art inline CO2 diffuser, 10 lbs pressurized tank, CO2Art Pro SE Dual Stage Regulator, set at 2 bubbles per second. But I am hardly getting any pH drop. This means that the rate of my out-gassing is faster than the rate of my CO2 injection.

So I tried increasing the rate at 3 bubbles per second, but this will also mean I may need to increase my lighting intensity (or adjust the height of my light nearer the water surface), more fertilization, etc. I just want to change one factor, which may mess up my tank’s established balance. Plus, the fact my planted aquarium is in our terrace, plenty of ambient light from the sun but no direct sunlight, which kind of makes it hard to balance everything. I found out that just by simply lowering the outtake of my filter towards the substrate and leave the water surface agitation to my fans and deploying submersible pumps to distribute the CO2 (prolonging the contact in water to dissolve) and nutrients, yield the .6 drop in pH that I am after (no changes in my lighting nor fertilization, minimal to no visible algae, controlled growth and thriving plants).

It is up to the hobbyist to find the balance of their own tank.

Stressing This Out Again

I want to stress again. Every planted aquarium is unique. What worked for others may or may not work for you. We all have a differing degree of planting, tank sizes, water parameters, water sources, stocking, maintenance schedules, lighting (intensity and spectrum), injecting co2 or not, filtration, aeration, substrates, even external factors like extreme weather conditions and ambient temperatures, etc. it is up for the hobbyist to find the balance of all these factors.

You can also ask for help from others who are willing to help and have the experience. A sensible co-hobbyist will ask some questions first before jumping to conclusions (even if he had the same symptoms before) like what is your water parameters, how old is your tank, did you perform any tank cycling, or do you even know what tank cycling is, what did you changed before the problem happens, what is the size of your tank, filtration used, the substrate used, how is your stocking, your feeding schedule, and maintenance, to name a few.

From your answers, he may be able to create a hypothesis and test it. He may ask additional questions to prove his theory further until you both reach a conclusion and resolve the problem.

Conclusion

Carbon Dioxide is naturally produced in our planted aquariums from the breakdown of organic matter and beneficial bacteria and faunas respiration. We also compared the CO2 levels from natural environments such as lakes, rivers, or spring water with our enclosed environment. That CO2 levels in our tank will be in equilibrium with the atmosphere (at 2-3 ppm).

The decision to inject CO2 in our planted aquarium depends if you want faster and more robust plant growth, and you are determined to keep up with the maintenance and start-up cost. CO2 injection tuning is both science and an art that you may want to experience with your journey on this hobby.

It requires you to balance your CO2 injection with your lighting, fertilization regime, and other water parameters and need more time and experience to achieve.

We also covered the many ways of measuring the CO2 levels in our planted aquariums and the pros and cons of each.

Finally, we tackle why providing water surface agitation during CO2 injection might look counter-intuitive but actually will help the hobbyist to fine-tune the CO2 injection rate and distribution along with providing water agitation to prevent dangerous levels of CO2 building up, achieve the 1 pH drop in just a few hours, and faster and robust plant growths with minimal to no visible algae.

Closing Remarks

I hope you enjoyed this article. If you have additional questions or want to share your experiences with the Dissolved Carbon Dioxide parameter in your planted aquarium, please leave a comment below. Next, we will be discussing the Chlorine/Chloramine Parameter for our planted aquariums.

8 Comments

  1. Lynne

    Wow, I had heard that there was a lot that goes in to maintaining an aquarium but I had not idea it was so technical. I’ve always loved looking at aquariums, at the plants and the fish and other aquatic animals. It is so peaceful and beautiful. It looks like if I want to have my own aquarium one day I will need to get a professional to help me set up the whole system and monitor the CO2 levels and the PH!

    Reply
    • Lemuel Sacop

      Hello Lynne,

      Thanks for taking the time visiting and appreciating my articles. To be honest to you, I even didn’t know half of what I know now when I was starting with this hobby. It may seem a lot to consider with this hobby, but start slow, do your research, start with a good water parameters, you don’t even have to inject CO2 from the start, choose undemanding plants to lights and CO2, cycle your tank, get the hang of keeping a planted aquarium first, start with just a simple scape, do not overfeed and overstock fish, and everything will fall into place.

      It is a good start for you to find this website and every article in here is in sequence and will help you along the way. Again start slow.

      You can choose to seek help with a professional aquascaper to set you up near your location, but you have to learn how to maintain it still. And a sensible aquascaper can help you with that. 

      After you had done your research, it is more rewarding if you are the one to setup your planted aquarium from the start, you will learn a lot, you may commit mistakes, but I know you can do it and see your plants grow and your faunas happy.

      Once your tank is cycled and stable, all you need to do is change the water 25 % once or twice a week, occasionally trim plants and re-plant. 

      Reply
  2. Rohit

    Very informative article for hobbyists. I understand now why water is the most important parameter in the environment. Given various fertilizer, water has the most effect on an aqua environment system. That is why it is necessary to test water quality from the plantation to growth and take actions accordingly.

    Your post clearly explains the level of carbon-dioxide and troubleshooting if it is too low or too high. Measuring Ph level is a sure shot way of determining the carbon dioxide content.

    It is very interesting to note that carbon dioxide accumulates in light off and quickly depletes when light is on.

    Overall a very well-laid out article on the right way of monitoring and controlling water quality.

    Thanks for sharing this article.

    Reply
    • Lemuel Sacop

      Thank you so much Rohit for visiting my website and taking interest in my article. Take note, this is just one water parameter, there are more critical water parameters that were discussed prior and after this article, so please make sure to visit those too. 

      Reply
  3. Neksummi Matthias

    You’re absolutely right saying every healthy ecosystem requires a balanced environment. And I quite agree with you that the most important of all the balanced factors that go into a successful planted aquarium is the quality of the water used in our planted aquariums.

    I’m completely new to this concept and I found the article a bit above me. But I’ll bookmark the page and come back to study it in more detail.

    Nice write up.

    Reply
    • Lemuel Sacop

      Hello Neksummi,

      Thank you for visiting my site and finding my article informative. I hope in some ways, I was able to help you decide in trying a planted aquarium in your own home.

      Reply
  4. Christine

    I used to have an aquarium, decades ago. My father and I maintained it, and I remember how much work it was. You have a big responsibility to provide a breathable environment for fish and plants.
    I always wanted to have a large aquarium again, but it is a lot of work and I have so many other things to do during the day that I have held off until now.
    I did not know that you could inject carbon dioxide into your aquarium. I also found it interesting to learn that some plants change colors because they are stressed, for example the red colors. Do you have an article about that? I would love to read more about it.
    What do you recommend using instead of drop checkers?

    Reply
    • Lemuel Sacop

      Hello Christine,

      Thank you for sharing your experiences with your aquarium. I wonder if it is planted or not. Yes, not all colored plants means a happy plant, I will discuss it in a future article. The most accurate measure of dissolved co2 in your water column is the KH-pH chart. Drop checkers just give you a false security/satisfaction and won’t allow you to learn properly distributing your co2 across the whole tank.

      Reply

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