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Optimizing CO2 in non-injected tanks

MichaelJ

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Hello,
I am looking for ideas to optimize the CO2 levels in my non-injecting tanks.

In both my ~150L (40 US Gallon) tanks I am striving for the lush wild overgrown look - I have no algae to speak of and good plant health and growth overall - for a low-energy tank at least… I already trimmed down and cut back on the plant mass a bit (and will probably do more) - I think this may be the most significant thing I can do anyway, but I am always curious to what people are recommending in addition.
I am going to increase surface agitation a bit (without stressing the fish and frogbit) to get that slight extra bit of CO2 uptake. Maxing CO2 in Low Techs
Since I started the tanks about 10 months ago I’ve run them almost constantly at about 26-27C (79-81F) and thinking of gradually lowering temps to about 24-25C (76-77F). My understanding is that as water temperature goes down the CO2 uptake from the air and the bio-availability of CO2 goes up? Lowering the temperature will also slow the plants metabolism causing slower growth and lessen the plants uptake of CO2 as well, so that all sounds like a win-win theory - albeit fairly marginal I assume?
My light levels have always been quite low - long hours (11) but low intensity and lots of remarkably thriving frogbit to provide additional coverage. I am wary about changing my light setup as I have reached a very good compromise on that part, but I suppose cutting back an hour or so would somewhat increase the CO2 production from the plants themselves.

Other tweaks I can make?

Cheers,
Michael
 
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PARAGUAY

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If you have soft water you probably have decent background levels of CO2 Maybe w/changes regularly done keep the levels up? This could explain your plants doing really well. If not a % of rain water added. I have read 22 degress is a prefered temperature for most aquatic plants but depending what fish you keep of course. Adding liqiud "carbon like Easylife but that moves the tank up a little from lowtech. Someone more knowledgable may reply
 

MichaelJ

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@PARAGUAY Thanks. Yes, my water is somewhat soft I suppose (KH 5-6 / GH 5-6). I don't know how much that plays into the CO2... what I am trying to accomplish is somewhat of an equilibrium between plant mass and available CO2. By optimizing the CO2 usage (lower plant metabolism, trimming and cutting back etc.) and uptake from the air (lower temp, surface agitation) I was hoping to give my plants mass a bit more "buffer". Of course, there is no way around cutting and trimming back on a regular basis.
Adding liqiud "carbon like Easylife but that moves the tank up a little from lowtech. Someone more knowledgable may reply
I am not quite sure about liquid carbon - I used Excel at some point long time ago, but stopped dosing it as my Vallisneria especially started to die. I know others have success with it - especially combined with CO2 injection.

Cheers,
Michael
 

PARAGUAY

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Your right liquid carbon affects some stems egeria as example but some of the can grow emmersed types are ok . Vallis seems particarly in not thriving with LC. Mosses were reportedly also not liking LC. Dennerle do Bio LC not sure about it. Think adding remineraliser and a couple of WC weekly will keep plants happy
 

MichaelJ

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@PARAGUAY Thanks. Yep, my mosses also didn't cope with the LC... but the mosses was never doing great anyway. I think I'll just keep it as it is for now with the changes I've made. I lowered the temp about 1 degrees C, increased surface agitation a bit with surface skimmers that also provide aeration and cut an hour off my light cycle. I am doing 40-50% WCs per week already with a DIY remineralizer and that seems to work fine.

Cheers,
Michael
 

ScareCrow

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I've switched to rain water and have been using a siesta period to try and make the most of available CO². I can't tell if it's made a difference significant difference because I also rescaped at the same time. I'd say there is some improvement in plant health but the main benefit is getting to view my tank in the morning and evening.
 

MichaelJ

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Hi @MichaelJ

You may want to take a look at posts by @Christel. I think she prescribes what you have said above.

JPC
Hi @jaypeecee Thanks! I will conduct a search through her posts.

I've switched to rain water and have been using a siesta period to try and make the most of available CO².
Hi @ScareCrow I would have to set up a container to see if collecting rain water is a feasible route in the spring/summer/fall months. We do get a lot of rain around here, but I do not know how suitable it is for aquarium usage - I would guess that it is - perhaps with some active carbon filtering to remove potential toxins?

Cheers,
Michael
 

ScareCrow

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I would guess that it is - perhaps with some active carbon filtering to remove potential toxins?
Personally I don't use active carbon but it might help to remove heavy metals and other non-organic pollutants. As a basic check I test the TDS before I use it. If it hasn't rained for a while, I divert the water from being harvested for a few hours, to reduce the chance of pollutants entering the storage barrel. There is a more sophisticated approach called first flush, which I'd like to setup one day.
 

Christel

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Of course, you can use rainwater, of course, it must be filtered. The problem is that sometimes you do not have clean rainwater. If it stands too long, bacteria form - blue algae then come in the aquarium. It is especially important to create a stable environment in your aquarium. Using different water again and again leads to unstable conditions. I tried this for a long time for ecological reasons. But then there was no rain for weeks.....
 

MichaelJ

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Of course, you can use rainwater, of course, it must be filtered. The problem is that sometimes you do not have clean rainwater. If it stands too long, bacteria form - blue algae then come in the aquarium. It is especially important to create a stable environment in your aquarium. Using different water again and again leads to unstable conditions. I tried this for a long time for ecological reasons. But then there was no rain for weeks.....
Hi @Christel Yes, the inconsistency worries me as well. And of course, for me here in Minnesota it would only be feasible to collect 6-7 month out of the year because of the cold and storing the water indoor is not practical in my case. We do get a lot of rain here though.
Cheers,
Michael
 

zozo

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Some people use vinegar in low-tech aquariums and report increased plant growth... I guess from a chemical view this is because any aquarium contains bases as well as acids... Adding an acid reacts with the bases and it releases CO².
Now I'm far from a chemist thus for anybody more familiar with the theories. Please correct me if I'm wrong and there are other reasons why adding an acid could be beneficial for plant growth!?

In some old-school LFS's you still can find Oakleaf extract which is also a rather acidic solution. I know it was very popular in the past for adding humic substances and regulating Ph. It might still be used today.

Regarding the aquarium, I have no personal experience with regularly adding acid to the water. I don't like to play the chemist with my tank and rather leave it as is. All tho I know small amounts don't do harm and do use vinegar for cleaning the stains from the glass and some of it ends up in the water. Also no idea about the correct amount of dosages I guess as long as it is in a safe Ph range it's ok. But adding too often too much pH might crash below safe ranges. It's something to be cautious with.

But in theory, adding acid will boost CO² availability.
 
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MichaelJ

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Some people use vinegar in low-tech aquariums and report increased plant growth... I guess from a chemical view this is because any aquarium contains bases as well as acids... Adding an acid reacts with the bases and it releases CO².
Now I'm far from a chemist thus for anybody more familiar with the theories. Please correct me if I'm wrong and there are other reasons why adding an acid could be beneficial for plant growth!?

In some old-school LFS's you still can find Oakleaf extract which is also a rather acidic solution. I know it was very popular in the past for adding humic substances and regulating Ph. It might still be used today.

Regarding the aquarium, I have no personal experience with regularly adding acid to the water. I don't like to play the chemist with my tank and rather leave it as is. All tho I know small amounts don't do harm and do use vinegar for cleaning the stains from the glass and some of it ends up in the water. Also no idea about the correct amount of dosages I guess as long as it is in a safe Ph range it's ok. But adding too often too much pH might crash below safe ranges. It's something to be cautious with.

But in theory, adding acid will boost CO² availability.
Hi @zozo I suppose that might work for a small amount of co2 for a short amount of time. I am wary about adding too many chemicals to my tanks as well - especially not knowing the potential downsides. I used to be caught up in targeting a specific PH range in part because of misconceptions about CO2. Months ago I essentially decided to not 'care about PH' anymore and just go with whatever my 50/50 tap/RO mix WC water is (somewhere around 7.2-7.4). Even if I could boost CO2 by adding some chemicals / acidic substance I suspect the effect would be very short lived. I much rather have a lower, but consistent and sustainable CO2 level that balances with the plant mass and uptake that the plants have adapted to, than the occasional boost or spikes you might get from adding chemicals. I do have drift wood in my tanks, mainly for decor, but that also tend to acidify the water a bit.

Cheers,
Michael
 
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zozo

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Here is a podcast about the subject from somebody who did.

:) Another theory I once did try in practice but was a rather short-lived experiment because the equipment broke down.
Since I have a tank with a wet and dry trickle sump and the bacteria in the trickle media excrete CO². Thus I did put a lid over the trickle part and did put in a small DC12 volt air pump salvaged from an old coffee machine. And hooked a ceramic diffuser to the tubing.

In theory, the naturally produced CO² from the sump is pumped back into the tank. Now I have absolutely no clue how much CO² will be produced in there, but whatever comes out of it definitively is being reused, and is a slight optimization.

It took a few months for the old air pump to break down and I didn't like the noise that much. :) So I didn't continue the experiment. I wasn't planning to continue with placing a VAC 220 volt air pump in a wet environment. Also can't say it made a difference... But it doesn't change the fact that bacteria in trickle sumps fart a small amount of CO² while doing their job. Then why not catch it and use it, if it doesn't help then it won't hurt either.
 
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Tim Harrison

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I think soil substrate is an invaluable source of carbon and nutrients. Good oxygenation is really important too, increasing decomposition of the organic matter in soil and the subsequent release of CO2.

Hard water has its advantages. Some plants can manufacture carbon from bicarbonates and thrive in hard water, vallis, Anubias, Crypts, Aponogetons, Echinodorus to name but a few.

Also you're okay to reduce the temp of the tank to 23 degrees. All my tanks have been kept at that temp.
 

zozo

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Another one, but this ain't optimizing but actually injecting... An old-school trick from gardeners used to grow better plants was the use of gas burners. Such as gas-burning greenhouse heaters. It heats the greenhouse and the gas flame produces extra CO². And this is a proven concept that works for terrestrial plants.

I actually have noticed myself in the past when we still had a water heater in the bathroom with an atmospheric gas burner and a pilot flame taking the needed air from and also exhausting in the same room. Anyway one day I noticed that the plants in this bathroom did exceptionally better than the same plants outside this room. I asked my neighbor farmer about it and he told me, so I learned about the use and benefit of gas-driven greenhouse heaters. And what my old-school water heater with pilot flame actually was doing, was filling the bathroom with extra CO².

Nowadays due to safety regulations, those water heaters are no longer in production.

Bottom line, terrestrial plants in a small room with a constant burning small gas flame definitively have an advantage from the extra CO² from the flame.

I always wondered what if you would have an aquarium in such a room with an air pump and an airstone?

What about a fireproof cabinet with a tiny gas burner and an air pump in it? :lol:
 

MichaelJ

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I think soil substrate is an invaluable source of carbon and nutrients. Good oxygenation is really important too, increasing decomposition of the organic matter in soil and the subsequent release of CO2.
Very true. Walstad points that out as well. I try to keep a good circulation with no stale or dead areas around the tank and try not to stir up the substrate too much when I clean during my weekly WC.

Hard water has its advantages. Some plants can manufacture carbon from bicarbonates and thrive in hard water, vallis, Anubias, Crypts, Aponogetons, Echinodorus to name but a few.
Agreed. Eventhough I keep mostly soft water fish, I do try to not go too soft (currently around GH 5-6) and my Crypts, Anubias (a couple are flowering now) and Swords are doing great. My Vallis are struggling a little bit, probably due to the soft water.
Also you're okay to reduce the temp of the tank to 23 degrees. All my tanks have been kept at that temp.
I've seen that recommendation before. I think 23 C is too cold for my livestock (in particular the Rams and Cardinals). My current compromise is 25 C - some claims thats the lower end for Rams, but mine are doing fine it seems.


What about a fireproof cabinet with a tiny gas burner and an air pump in it? :lol:
Now that's an idea that has "DANGEROUS FUN" written all over it :lol: Not to mention the fury of my wife:lol:

But it doesn't change the fact that bacteria in trickle sumps fart a small amount of CO² while doing their job. Then why not catch it and use it, if it doesn't help then it won't hurt either.
I like the alternative ideas, but I think I am just going to rely on what the substrate in the tank will do when organic matter decomposes.

Cheers,
Michael
 

Tim Harrison

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I think 23 C is too cold for my livestock (in particular the Rams and Cardinals
For what it's worth, I've kept both at that temp, often together, and both species thrived. But you're the best judge of what works in your tank ;)
 

John q

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My current compromise is 25 C - some claims thats the lower end for Rams, but mine are doing fine it seems.
Rams are a bugger to keep at the best of times due to mass farming and inbreeding etc, I think if you've gotten decent stock then they may well tolerate slightly lower temps but I've personally never had any luck with them below 25⁰c.
My Vallis are struggling a little bit, probably due to the soft water.
I have vallis in lowtech softwater tanks 2~3 kh and 3~4 gh and they grow like weeds. I add a few catappa leaves to lower the ph a bit, not sure if this helps them in any way.
 
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