In search of middle-earth - a quest for a middle energy tank

[Yugang]

I wouldn't worry prematurely - it might be fine!

This is also my intuition, and I would have two thoughts to justify any optimism.

First would be @sudiorca amazing tank, and we could argue that injecting just a little (as compared to what is usually advised for CO2 injected tanks) is in fact approaching what he is doing, but making it just a bit easier with some support from a little injection so that we don't rely as much on the soil. My disadvantage however is the higher temperature in the tank, compared to @sudiorca 's.

The other hint would be that I have seen hardly any data on natural waters (like Amazone basin) where CO2 is as high as 30 ppm, so we could hope that most (semi) aquatic plants evolved to be comfortable with lower levels as long as we give them some time to acclimatise, and could still handle higher light intensity for them to grow compact and with nice coloration.

This is all just hope, I admit. I believe the experiment needs a couple of weeks, and only if my tank strongly deteriorates will I bring my reactor back and follow again more conventional CO2. So far I love the simplicity of the injection, and the slow growth.

 

[Yugang]

I am now nearly 2 weeks into my experiment with around 10-15 ppm CO2, same medium-high light and same EI ferts. So far the tank is doing fine, and its owner happy with the slower pace. It seems that plant growth came initially almost to a total standstill when I lowered from around 30 ppm to 10-15 ppm, but it is either my imagination or the real start of adaptation that I see some growth again in the second week. I did careful maintenance, some stems really had no chance of survival and I decided to remove them to lower waste organics, but so far no issues with algae or signs that the tank won't make it.

I love this experiment, and if anything to change I may go even lower in CO2 in the next phase to try and find the limit. I have no illusions that I am a good scaper, so when I post future tank picks it is up to our fellow members to see if the limitations are in the CO2 or more with its owner's limited skills.

So here I like to reach out to some of our most experienced members. I took the top 4 tanks from the recently announced Korea International Aquascaping contest, thanks for the post @Art, and asked myself which of these would NOT be possible with low 15 ppm CO2 injection and perhaps some reduction in light intensity as well? Are we saying that all these top ranking tanks need at least 30 ppm CO2? If anyone could make an educated guess, that could give some really nice insights.

2024 KIAC TOP 10

Announcement of the final results. Top World Ranking 1~10. You can see the judges' reviews for each individual work.

kiac.kr

 

[Krandall]

Yes, there is a way to do it, and dare I say, it was the original way of dosing CO2. Use of C02 in tanks has been around for a long time, at least 40 years plus, and before high intensity lighting like LED, T5 or metal halide was around. People simply supplemented with CO2, ie replacing the CO2 that the plants start taking out when they start to photosynthesise at lights on. There used to be guides as to you many BPS depending on tank size, and those that could afford it used a CO2 meter and set it to turn on the CO2 when the pH started to increase after lights on. I ran a tank using the latter method for many years and it worked very well.

A couple of shots of a tank of this type. Sorry for the photo quality. That's what you get with 30-odd year old slides! LOL!



This tank did not have a soil substrate. It had a CO2 reactor in the left corner behind the Crypts. For micros, I fertilized from 4 liter bottles of "Tropica Mastergrow" which Claus used to send me directly from Denmark. I used "Stumpeez" Stump remover for N&K, and my tap water had 3ppm of phosphate, so water changes took care of that, even at a time when ADDING phosphate to an aquarium was anathema! It had a "traditional" (for the time) clay under fine gravel substrate. Lights were 6 T-12 flourescent bulbs... The most that would fit over the tank. No idea on the PAR. We had no way of measuring it in those days. But NOTHING like what many people routinely run these days.

One of the fantastic things about this tank was its longevity. While I certainly replanted it and moved things around, I never replaced the substrate. This tank ran for over 20 years without a full reset. The most I did was to pull plants from 1/3 of the tank at a time when it became too root bound. (learned this technique from Claus Christensen also). When I finally took the tank down, it was not because it was not still growing plants well, but because the tank was second hand when I got it, and I was worrying about the aging silicone seals and my hardwood floor underneath it!

 

[ElleDee]

View attachment 5602

I love this! This is exactly the vibe I'm going for with my next build. There's something about this style that has a more relaxed feeling than scapes that are more hardscape focused or jam packed with high maintenance stems, but it still hits all the color and texture contrasts to generate interest and drama. I know you are a true pro and don't need me to tell you your aquarium is nice, but there are lots of tanks that look beautiful, yet hardly any that I would truly want to own. Inspiring!

I used "Stumpeez" Stump remover for N&K,

I had no idea potassium nitrate was used as a stump remover! The only stump remover I was familiar with was an herbicide, definitely not fit for an aquarium of any sort.

It had a "traditional" (for the time) clay under fine gravel substrate.

I'm interested in this. How thick was this layer and was it a particular type of clay?

One of the fantastic things about this tank was its longevity. While I certainly replanted it and moved things around, I never replaced the substrate. This tank ran for over 20 years without a full reset. The most I did was to pull plants from 1/3 of the tank at a time when it became too root bound. (learned this technique from Claus Christensen also). When I finally took the tank down, it was not because it was not still growing plants well, but because the tank was second hand when I got it, and I was worrying about the aging silicone seals and my hardwood floor underneath it!

Was there a technique to not disturbing the clay layer when you uprooted everything? Or was that not really an issue?

 

[Krandall]

I had no idea potassium nitrate was used as a stump remover! The only stump remover I was familiar with was an herbicide, definitely not fit for an aquarium of any sort.

It was THE stump remover, until the Oklahoma bombing.

I'm interested in this. How thick was this layer and was

The typical recommendation was 1” of gravel mixed with red clay of some sort. Capped with 2” of washed gravel. In practice it didn’t need to be. This practice came from Dupla, and “The Optimum Aquarium”. The idea was to increase the CEC of the substrate, and provide a nutrient sink for nutrients captured from the water column over time. That part still holds up to what we know today. The “red clay” part came from the belief that plants could access the iron sequestered in this clay. Of course we now know that they cannot in a very meaningful way.

Here in the US, where Dupla clay was very hard to obtain, and SUPER expensive, we experimented with a number of different substances instead. Redart clay was very popular, some people dug clay from their yards, or clay banks in streams. Merrill Cohen, who I mentioned in the history thread, sold his own brand. Then Karl Schoeller, a buy in the midwest, started marketing a clay he called “Substrate Gold”. While he never said what was in this, it worked really, REALLY well. Better than any other clay substrate amendment I ever used. What we all strongly suspected is that this clay was laced with NPK, which gave the plants a big initial boost.

And you didn’t use a ton of clay… a couple of handfuls mixed into the substrate was plenty.

People were experimenting with soil substrates at the same time… some successful, others not so much. I think the best of the soil substrate methods is Sean Murphy’s mineralized topsoil method, which has pretty much the same benefits of Substrate Gold. More work, but no cost!

“Was there a technique to not disturbing the clay layer when you uprooted everything? Or was that not really an issue?”

It wasn’t really an issue once the tank was settled. It was like aquasoil, Seachem substrates, etc. Sure, you got some water clouding when you disturbed it, but it settled out again by the next day.

I think you could get pretty much the same result today by setting up a tank with SafeTSorb. Except, perhaps, that quartz gravel holds the plants more firmly than the lighter weight clay. But the tank, I believe, would have the same kind of longevity.

The biggest downside to these substrates is that it is difficult to grow small, fine rooted foreground plants in them. So if that’s your thing, aquasoils are a much better option.

This is another tank of this type, this was a 125G, though this was in the days of T5HO’s… So this had a lot more light. Still less CO2 than many people run today, though… probably 15-20 mg/L. No pH controller, just a solenoid to turn it off at night. Oh, and there WERE a lot of fish! But slow film made the fast swimmers disappear!

 

[hypnogogia]

see post below.

 

[hypnogogia]

A couple of shots of a tank of this type. Sorry for the photo quality. That's what you get with 30-odd year old slides! LOL!
View attachment 5601

View attachment 5602
This tank did not have a soil substrate. It had a CO2 reactor in the left corner behind the Crypts. For micros, I fertilized from 4 liter bottles of "Tropica Mastergrow" which Claus used to send me directly from Denmark. I used "Stumpeez" Stump remover for N&K, and my tap water had 3ppm of phosphate, so water changes took care of that, even at a time when ADDING phosphate to an aquarium was anathema! It had a "traditional" (for the time) clay under fine gravel substrate. Lights were 6 T-12 flourescent bulbs... The most that would fit over the tank. No idea on the PAR. We had no way of measuring it in those days. But NOTHING like what many people routinely run these days.

One of the fantastic things about this tank was its longevity. While I certainly replanted it and moved things around, I never replaced the substrate. This tank ran for over 20 years without a full reset. The most I did was to pull plants from 1/3 of the tank at a time when it became too root bound. (learned this technique from Claus Christensen also). When I finally took the tank down, it was not because it was not still growing plants well, but because the tank was second hand when I got it, and I was worrying about the aging silicone seals and my hardwood floor underneath it!

I just love the longevity of tanks like this. For me there’s always been an irony about high energy nature aquariums that have a short lifespan and consume lots of energy, when in many other aspects of life we seek to find ways to conserve energy. Nature is slower moving and for me tanks that are medium energy sit better with the concept of conservation and reproducing our own little slice of nature.

 

[Krandall]

I guess I am too busy (or too lazy?) to keep after high-driven stem tanks for any period of time.

 

[Mr.Shenanagins]

I’m a fan of the KISS method too, and I like using terrestrial soil too in a mineralized state. I have no plans to change the substrate ever, and I really don’t see a need to when things are growing like you said with no issues

 

[ElleDee]

Thank you for this extensive reply! I don't like using aquasoil (not because it doesn't work - it's expensive, I don't like how it looks, or how lightweight it is), so these "old school" substrates are all very interesting to me. I'm sure it's all been tried before.

The “red clay” part came from the belief that plants could access the iron sequestered in this clay. Of course we now know that they cannot in a very meaningful way.

Oh? Is this because of the lack of organic matter in this particular substrate or a ph issue?

People were experimenting with soil substrates at the same time… some successful, others not so much. I think the best of the soil substrate methods is Sean Murphy’s mineralized topsoil method, which has pretty much the same benefits of Substrate Gold. More work, but no cost!

That method is still used fairly often, though I don't know if people use all the same amendments or not. I have a bag of garden mix "mineralizing" on my patio right now, by which I mean it's just sitting there in the heat and rain for several months. Laziness at work!

This is another tank of this type, this was a 125G, though this was in the days of T5HO’s… So this had a lot more light. Still less CO2 than many people run today, though… probably 15-20 mg/L. No pH controller, just a solenoid to turn it off at night. Oh, and there WERE a lot of fish! But slow film made the fast swimmers disappear!

View attachment 5612

Another beauty! Thank you for sharing.

 

[Mr.Shenanagins]

I have a bag of garden mix "mineralizing" on my patio right now, by which I mean it's just sitting there in the heat and rain for several months. Laziness at work!

Seems legit, did the same thing

 

[Krandall]

Oh? Is this because of the lack of organic matter in this particular substrate or a ph issue?

Because of the way it is chemically bound.

I don't like using aquasoil (not because it doesn't work - it's expensive, I don't like how it looks, or how lightweight it is), so these "old school" substrates are all very interesting to me.

It is kind of ugly, isn’t it. Of course, it is entirely possible to hide it with care, just like any other substrate. Most aquascapers use cosmetic sands, etc., in the visible areas at the front of tanks.

The weight is something that you do learn to work with over time. That doesn’t bother me. As I said, gravel can be too tough on many very fine rooted plants. And if you don’t like the weight of aquasoils, you probably wouldn’t like SafeTSorb either. Which is removing a very pretty, very inexpensive, very viable option from your “substrate toolkit”. I like it a lot.

That method is still used fairly often, though I don't know if people use all the same amendments or not. I have a bag of garden mix "mineralizing" on my patio right now, by which I mean it's just sitting there in the heat and rain for several months. Laziness at work!

IMO, may people who try to work with soil use “potting soil” or commercial “top soil”. Both are largely organic material, and likely to cause big problems In the bottom of an aquarium, especially if used in large amounts. Then people DO use them in large amounts. Not just a handful or two mixed into the bottom layer of gravel.

When the people who originally used soil in aquariums it was not plastic bags of man-made stuff. It was REAL soil, with the top layer of organic material scraped away first. And then it was mixed with the gravel, or put in a thin layer under the gravel. Not a thick, bubbling bed of smelly mud.

I hope you are joking, and know that mineralizing top soil requires actually submerging it in water for an extended period of time, right? It’s still not my favorite way of setting up a tank, but it’s the ONLY way I’d use soil…

 

[Mr.Shenanagins]

I hope you are joking, and know that mineralizing top soil requires actually submerging it in water for an extended period of time, right? It’s still not my favorite way of setting up a tank, but it’s the ONLY way I’d use soil…

The method I’ve always followed requires repeated cycles of “soaking” and allowing to dry via sunlight. This results in a sandy/airy substrate and this stage I was under the impression was the “mineralized” state. I have not had issues with this practice

 

[Dennis Wong]

Late to this thread because it has been a busy year for me... @Yugang are you really from Asia? Lower CO2 levels are very commonly used in Asia. I've travelled and seen shops from Thailand to Japan, China, Malaysia, Indonesia etc... most of them run very low CO2 levels (i.e. my guess is between 5-15ppm range). The 30ppm rhetoric is really only pushed hard on online forums, and usually by the crowd that grows/attempts to grow more difficult species. In the commercial world out there, lower CO2 levels are common (and the norm) because like you said (or maybe like I said,) it works for most common species.

After buying the Oxyguard CO2 analyzer, which allowed me to get very accurate CO2 readings, I went around and tested tanks in local shops. Readings were all over the place, some simple tanks had 30+ppm, other well planted tanks with colorful species had 15ppm. The few take away points I had:
- Gauging CO2 levels is difficult for most folks and the levels vary greatly depending on amount of surface agitation, and efficacy of injection methods, and for most casual hobbyists there is no easy way to gauge levels.
- For folks growing difficult species, erring on the side of injecting more maybe beneficial.
- The high tech crowd tends to judge techniques based on the pickiest 1% basket of plants, which matches their goals but do not indicate what is generally out there in the market, so there is a huge bias based on that approach. The high tech forum crowd makes out less than 1% of the total planted aquarium market out there based on our (2hr Aquarist) commercial statistics.
- There are benefits to injecting more CO2 than required (say 30, 40 or 50ppm vs the 10-15ppm that will grow 98% of species out there), as the grow impact factor allows tanks to outgrow certain problems. However, out-growing problems is not the only methodology to manage a tank.
- One hint to differentiate tanks visually that have low CO2 levels is that there is much less branching of stem plants below a certain level (below 8ppm or so). However, this can also be caused by very lean nutrient levels (principally N) or very low light levels (say below 70 PAR). However, adjusting for those 2 factors, stem plant branching is quite a good indicator of long term CO2 levels in a setup.

On the other side, I've been testing non-CO2 injected tanks and depending on how they are set up, they can have very different CO2 levels as well. I will elaborate further on this when I have time to get to writing on the data. I've measured 6-8ppm on non-CO2 injected aquasoil tanks. Non-aquasoil tanks with matured filters and heavy fish load seem to be able to hit 3-4ppm. Many low tech/non injected tanks can measure just 1-2ppm also depending on how they are setup, so low tech tanks vary greatly. Using organic decomposition and still water, I can get stagnant soil samples to produce 20ppm of CO2 in a small water body. (which may hint why smaller bowl type low tech tanks can be very successful). But managing the CO2 angle is definitely the key in having a successful low tech tank. Folks have it wrong then the approach low tech tanks thinking that they can work without CO2 - it is the opposite, the key is setting up a low tech system that generates meaningful CO2.

I explain a lot of my findings after collaborating results I got from using the Oxyguard CO2 analyser here: How to measure CO2 levels in an aquarium

haven't written much on the low tech side because I haven't had time yet.


My own plant holding tank at office at nearly 50ppm of CO2.


This shop tank tested slightly below 20ppm of CO2. [Aquatic avenue/Redhill- Singapore]. Note the rather picky species growing decently well such as Rotala florida etc. *Tank grown with APT Complete


Grew this tank in for a recent exhibition. Most of the time the levels were around 20ppm, still, it took just 7 weeks to grow this in from scratch.


A fish only tank with matured filter measured 5ppm of CO2. This is 4 to 5 times more than some other planted tanks that are setup with inert substrate (which measure 0-1ppm of CO2). There is also the factor that all these measurements are residual levels of CO2. A low tech tank might be say generating 5ppm of CO2, and plant uptake is using up 4ppm, so the residual measurement is 1ppm. These are additional confounding issues when interpretating CO2 levels.

 

[Hanuman]

Lower CO2 levels are very commonly used in Asia. I've travelled and seen shops from Thailand to Japan, China, Malaysia, Indonesia etc... most of them run very low CO2 levels (i.e. my guess is between 5-15ppm range).

Agreed. Never seen anyone in Thailand pump as much CO2 as I have done it myself, not a single one, and I know quite a few people here in the hobby. All shops with planted tanks here will inevitably have CO2 injection but nowhere near the higher end of the CO2 injection spectrum. In fact you will see that most of these tanks have a CO2 diffuser with most of the CO2 just going straight up and minimal current moving the CO2 around. The idea being to slightly increase CO2 but that's it. Also I have never seen any shop using inline diffusers or reactor for that matter.

 

[Mr.Shenanagins]

Folks have it wrong then the approach low tech tanks thinking that they can work without CO2 - it is the opposite, the key is setting up a low tech system that generates meaningful CO2.

I think that about sums it up right there. A great and smart way to think about it. I’m wondering then if it would be ideal to run a filter in the hours in which the lights are not on so as to not have that off gassing that would impact a non injected tank. Is that too simple of a solution? Looking forward to your future write up on low tech Dennis

 

[Yugang]

most of them run very low CO2 levels (i.e. my guess is between 5-15ppm range). The 30ppm rhetoric is really only pushed hard on online forums, and usually by the crowd that grows/attempts to grow more difficult species. In the commercial world out there, lower CO2 levels are common (and the norm) because like you said (or maybe like I said,) it works for most common species.

This is really interesting to read @Dennis Wong and @Hanuman , I was not aware of that. I am also excited to see more and more evidence and experience with low CO2 ppm coming out in this thread, I would say it is about time as most fora and experts indeed have been advocating as high as possible (as long as livestock can tolerate) CO2 ppm for high tech, or otherwise just low tech with some CO2 generated in the soil. I personally see a lot of potential advantages that make it worth exploring low CO2 injection, or perhaps better to say rediscovering, mainly lower maintenance and MUCH lower CO2 consumption. Again, I am interested to explore this area, while not compromising too much on the lush and colourful plant growth.

@Dennis Wong , I am now at about 15 ppm and so far so good. My 2 dKH drop checker is lime green. My tank temperature is typically 28 degrees, sometimes a few degrees up, sometimes a few degrees down, probably similar to your Spore situation? Would it be realistic in your view to aim for a tank as yours below, and if so could I even go to perhaps 10 ppm and still achieve similar? Am I right in understanding that, despite lower CO2 levels, your tanks are still pretty high on lighting?

Grew this tank in for a recent exhibition. Most of the time the levels were around 20ppm, still, it took just 7 weeks to grow this in from scratch.

 

[Hanuman]

This is really interesting to read @Dennis Wong and @Hanuman , I was not aware of that. I am also excited to see more and more evidence and experience with low CO2 ppm coming out in this thread, I would say it is about time as most fora and experts indeed have been advocating as high as possible (as long as livestock can tolerate) CO2 ppm for high tech, or otherwise just low tech with some CO2 generated in the soil. I personally see a lot of potential advantages that make it worth exploring low CO2 injection, or perhaps better to say rediscovering, mainly lower maintenance and MUCH lower CO2 consumption. Again, I am interested to explore this area, while not compromising too much on the lush and colourful plant growth.

If you are looking at selling submersed plants as your main activity it makes sense to have higher CO2 concentrations as you will have plants grow faster and fatter. That was basically the reason why my CO2 was up to the roof. I could not wait to propagate certain plants. Other than that the justification to have (very) high CO2 levels becomes less evident and more a personal choice. If you look at emersed plants produced by companies cattering the hobby I wouldn't be surpised they did the same thing by increasing the CO2 concentration in their greenhouses. Maybe, maybe not but, in commercial greenhouses producing vegetables, I am certain they do it to increase yield. This is common practice. Heck, even me in my days of weed growing in the closet, I increased the CO2 concentration by producing a mixture of yeast and sugar. High were those times...!

 

[Dennis Wong]

This is really interesting to read @Dennis Wong and @Hanuman , I was not aware of that. I am also excited to see more and more evidence and experience with low CO2 ppm coming out in this thread, I would say it is about time as most fora and experts indeed have been advocating as high as possible (as long as livestock can tolerate) CO2 ppm for high tech, or otherwise just low tech with some CO2 generated in the soil. I personally see a lot of potential advantages that make it worth exploring low CO2 injection, or perhaps better to say rediscovering, mainly lower maintenance and MUCH lower CO2 consumption. Again, I am interested to explore this area, while not compromising too much on the lush and colourful plant growth.

@Dennis Wong , I am now at about 15 ppm and so far so good. My 2 dKH drop checker is lime green. My tank temperature is typically 28 degrees, sometimes a few degrees up, sometimes a few degrees down, probably similar to your Spore situation? Would it be realistic in your view to aim for a tank as yours below, and if so could I even go to perhaps 10 ppm and still achieve similar? Am I right in understanding that, despite lower CO2 levels, your tanks are still pretty high on lighting?

Hmm I'm not sure about 10ppm, though I'm quite sure 15ppm will do it based on what I observe in tanks where I have taken accurate readings. At lower levels, 5ppm difference (10 to 15ppm) is a 50% change which is significant. Among the many picky species in high tech tanks, the ones that do respond quickly to increased CO2 levels (say from 20 to 35ppm) that I can spot are the red Erio, Blood vomit, and S. Vichada, to less extent, Hygrophila sp Chai. For many other common species such as Rotala rotundifolia variants/macrandras, most ludwigias, I cannot spot the difference between a 20ppm vs 35ppm tank even with all my expertise.

The problem with growing with a tank like the one I did above is that your warmer temps (28) makes stem plants elongate a bit more vertically, and you require a bit more light to get enough branching to get a very dense canopy (you will probably need at least 200umols at the canopy area). The increased growth speed also means more frequent trimming. Higher temps also result in slightly poorer coloration for quite a few species. Bacopa salzmannii below grown at 31 degrees celsius (with a heater) on the left vs 24 celsius (my standard room temp) on the right, all other parameters are similar. The leaves are a couple of tones lighter and the stem is more green at higher temps, along with slightly longer internodes. This is similar across many other species.

 

[Hanuman]

Bacopa salzmannii below grown at 31 degrees celsius (with a heater) on the left vs 24 celsius (my standard room temp) on the right, all other parameters are similar. The leaves are a couple of tones lighter and the stem is more green at higher temps, along with slightly longer internodes. This is similar across many other species.

I assume that CO2 was compensated in the higher temp tank so that both tanks had similar CO2 content. Now I understand why my B. salzmanii never had that red stem.