Lean dosing pros and cons

[Sudipta]

Thank you all for this great thread, I've been wanting to participate for a while but couldn't catch up on my reading 🙂.
I wanted to discuss several points with you, the first of which concerns the amazing @Sudipta setup. I would like to quote a thread from MichaelJ (from another topic) which summarises the key elements :



With a similar configuration, I had found a few months ago the youtube channel of Yulia aquascape : https://www.youtube.com/c/YuliaAquascape





After reading the comments on his channel and watching the videos, here are the key points (I'm summarising) :

• No CO2 injection :

The author's assumptions : source of CO2 1. From fish inhalation 2. When the lights are off (Dark) the plants emit CO2 3. Skimmers also suck up CO2 elements from the outside air 4. When changing water (Water Change), new water contains CO2 (pearling plants for 2-3 days)?

• KH and GH : unfortunately unknown here, Yulia indicates that he uses well water, from the ground, rich in minerals but does not know the parameters
• pH : also unknown
• temperature : big difference here, he mentionned a water temperature of 25-30 °C
• Very low water column nutrients : same assumption here, he uses a liquid fertiliser which seems to be lean and doses once a week.
• Rich dirt DIY substrate and gravel here
• No mention of root tabs
• Merk Bio KCL fertilizer - (content?)
• No PAR data but 1. LED SAKKAI Pro 26W (Blue & White) 2. PHILIP LED 8W x 2Pcs (Warm) 3. DAY 47 Philip LED up to 12W x 2Pcs for a 60cm x 30cm x 40cm. So approx 1W LED/L. Even with a low PAR/W efficiency, I think strong lighting can be expected with such values. Given the density of the plants and colours also.
• 100% WC ! 3-4 days, sometimes 5 days & 7 days (pearling plants for 2-3 days)
• No/infrequent uprooting : same here
• No filtration !

So I see 3 big differences with Sudipta's tank: no filter here, relatively high temperatures and big water changes (for CO2 inputs). The plants are dense, the biomass should be high.
What do you think? I wanted to discuss other points but I will do so in another post.

wow.. these are really beautiful. Plants look really vibrant and healthy, significantly better than any of my non-CO2 supplemented softwater tanks. However, I am little bit confused as I see Amazon link for CO2 kit in most of his video descriptions. Are you absolutely sure that these are non-CO2 setups?

 

[Hanuman]

wow.. these are really beautiful. Plants look really vibrant and healthy, significantly better than any of my non-CO2 supplemented softwater tanks. However, I am little bit confused as I see Amazon link for CO2 kit in most of his video descriptions. Are you absolutely sure that these are non-CO2 setups?

In all his videos:


The above pretty much answers the pearling. Changing water so regularly you are bringing in CO2 nearly daily.

Here, with your hypotheses (which I also agree with) and with limited gas exchanges, I expect the rate to be maximum when the lighting are turned on and very low few hours later. We are typically in the fluctuating CO2 situations described by T. Barr, D. Wong and others, with great risk of unhealthy plants and algae +++. But nothing like that.
What is your opinion ?
My other hypothesis would be that ultimately without rich fertilization, plant growth is slowed down and the demand for CO2 is lower. But the substrate is still rich. And D. Walstad talks about this case of CO2 that can go down to 0 in her method, she recommends siesta to regenerate it. But this does not prevent fluctuations.
I'm confused on this point.

1. CO2 fluctuates as much in his tanks than in any CO2 injected tank (day/night). The idea of CO2 fluctuation is misunderstood IMO. It's not whether it fluctuates as much intra day (although that can have consequences under certain conditions), but whether it is erratic and inconsistence week after week. One also needs to consider lighting vs CO2 consumption. In the case of his tanks, CO2 is consistent in the way he does WC regularly and often pretty much maintais CO2 levels week after week. Plants will adapt and grow accordingly. He is also not bombarding those tanks with indecent amounts of PAR. Those are low to medium lit tanks. Nowhere near what you see in high tech tanks with 200umol as a minimum in many instances. Look at one of his 60cm tank with 2 x 12W LEDs perched at ~20 cm+ from the water surface.... That is was I call very low light. There is another one with 50W which is obviously higher energy but again, look at where the lights are positionned, quite high. I am pretty sure a PAR meter would read under 100umols at substrate level specially be cause he used cheap LED bulbs.

2. Those tanks are 100% heavily planted with fast growing stem plants. Algae has little chance in these scenarios considering the very rich, fertile substrate. Plants are nowhere being limited by nutrients. Also, note this innocuous comments in bold letters in the description:



Overall I am not impressed considering we only see 3-4 months worth of tank life. I call that the grace period where everything is basically at its prime and little exogenous intervention and management is needed. Plants are doing all the heavily lifting here. Aquascaper is merely cuddling plants. What would be more interesting to see is those tanks under the same regime after 6 months to a year. That would really be a test. But I bet those tanks are dismantled after 6 months or so because the amount of work required to maintaining them is high. Plus the grace period is over and you need to start adjusting things like ferts, trimming, etc etc.

This is what I dislike about these youtube videos. Often time they just show the beginning and great part and omit the rest. Then people are left with a biased opinion on what to expect if they do the same.

 

[Sudipta]

The above pretty much answers the pearling. Changing water so regularly you are bringing in CO2 nearly daily

Thanks for the information. That makes sense. I saw in one of his videos, he mentionned that sometimes he changes water 5 times a week and even every day occasionally. I am wondering if he is changing water during the light period. I have seen massive improvement in plant growth when I was doing daily water changes last summer (25% during light period) in one my non-CO2 supplemented softwater tanks while treating ich with high temperature (84F) and ich-X. I did that for 3 straight weeks and the plants did exceptionally well, even better than my other tanks where I was doing weekly water changes with lower temperature (75-77F).

 

[Hanuman]

I am wondering if he is changing water during the light period.

If I had to speculate I would say it's beneficial to do WC during the photoperiod since plants would be exposed to atmospheric CO2 which they can capture and store in their leaves. Josh made a comment in that regard and I would tend to agree.

I think it is important to say that the 80% water change exposes the plants to atmospheric gas and the plants then store those gases.

But regardless of doing it during the photoperiod or not I think it is still beneficial overall to do WC more often than not. It's not only about CO2 but also about removing organics and reseting fert levels. It would basically equate to what happens in a river where water flows and constantly brings new nutrient, CO2 etc. That's my theory at least.

 

[Wookii]

Aquascaper is merely cuddling plants.

You take it to a new level man! I'm making that quote of the day! 😂

I saw in one of his videos, he mentioned that sometimes he changes water 5 times a week and even every day occasionally.

That would explain it a bit then, as that would mean he is in essence dosing the tank with CO2 pretty frequently.

 

[Hanuman]

You take it to a new level man! I'm making that quote of the day! 😂

One got to laugh else it's a depressing life! That's my moto.

 

[Wookii]

One got to laugh else it's a depressing life! That's my moto.

Absolutely, very much mine too! 👍

 

[Guest]

If I had to speculate I would say it's beneficial to do WC during the photoperiod since plants would be exposed to atmospheric CO2 which they can capture and store in their leaves. Josh made a comment in that regard and I would tend to agree.

I think that's pretty much the nub of it. Aquatic plants adapted to life under water will be pretty good at absorbing gases from the atmosphere. So when they're exposed to 410ppm CO2, as opposed to 10ppm in water, via a daily water change you bet they're going to do okay, so no great mystery.

And I'm guessing they'll most likely store atmospheric gases in their aerenchyma to be used later on in the photoperiod upon re-submergence. This method of getting CO2 in to aquatic plants is nothing new I remember reading about it way back, not sure where, probably the Barr Report.

 

[Sudipta]

This method of getting CO2 in to aquatic plants is nothing new I remember reading about it way back, not sure where, probably the Barr Report.

I think you are referring to this. I was quite surprised last year when the plants did really well in relatively high temperature in one of my non-CO2 supplemented softwater tanks since I was changing water every day for 3 weeks due to ich issues. However, it made a lot of sense after I read Tom's post and also from a conversation with him.

Why water change day seems to grow aquatic plants better

Basic simple question: why do my plants seem to grow better/best the day of the water change? I do a large water change in the morning right after the lights come on, then late in the day, there is mad pearling and obviously better growth than any other day of the week. I've measured plant...

barrreport.com

 

[Gorillastomp]

Isn't pearling associate with the fact that you add fresh water high in dissolved oxygen ?

Because i make water change using my tap which comes from a well. I doubt this water is high in co2 and change water by the overflow method. I get mad pearling as well after a wc.

 

[Hanuman]

Isn't pearling associate with the fact that you add fresh water high in dissolved oxygen ?

Pearling is associated with plant consuming CO2 and producing/perspiring O2.

Because i make water change using my tap which comes from a well. I doubt this water is high in co2

I can't tell you for sure about your water specifically but typically well waters can have a very high CO2 content. So that is probably why you see lots of pearling specially if you have adequate amounts of light.

 

[Gorillastomp]

I can't tell you for sure about your water specifically but typically well waters can have a very high CO2 content.

How would you know this? My water is out at PH 8.3-8.4, if i let it sit a day its comes down to around 8.2 - 8.3.

 

[dw1305]

Hi all,

How would you know this? My water is out at PH 8.3-8.4, if i let it sit a day its comes down to around 8.2 - 8.3.

It can be a temperature (and / or) pressure effect. All dissolved gases are more soluble at lower temperature (and higher pressure), which means that if you do a 50% water change with cool water all that "spare" dissolved gas will come out of solution as the water warms.

In this case most of "pseudo pearling" the bubbles will be nitrogen (N2), purely because the atmosphere is ~70% nitrogen.

Water (at 25oC) holds, a maximum of, ~13 mg / litre dissolved N2 and 8 mg / litre oxygen (O2), everything else (CO2, Argon (Ar) etc) are just traces.

cheers Darrel

 

[_Maq_]

He does two very large water changes (>80% by the looks of it) per week, and so adds a good amount of dissolved CO2 to the system at those points...

Tap water, due to elevated pressure, often contains lots of dissolved air. There's no reason to expect significantly elevated content of CO2 from this source.
However, if a well water is the source, it may very well contain high levels of CO2. In lower parts of many wells CO2 rich atmosphere is the norm => partial pressure of CO2 is higher => water is full of CO2.

 

[Wookii]

Tap water, due to elevated pressure, often contains lots of dissolved air. There's no reason to expect significantly elevated content of CO2 from this source.

But air contains in excess of 400ppm CO2, so if that water has “lots of dissolved air” in it, it will be naturally much higher in dissolved CO2 than water that is in CO2 equilibrium with the air. This can be shown fairly easily by measuring the pH increase after allowing tap water to degas.

 

[_Maq_]

But air contains in excess of 400ppm CO2, so if that water has “lots of dissolved air” in it, it will be naturally much higher in dissolved CO2 than water that is in CO2 equilibrium with the air. This can be shown fairly easily by measuring the pH drop after allowing tap water to degas.

Will you explain? I think if I leave the tap water to degas, CO2 content would decrease, and pH would rise, as a result. Am I missing here something?

 

[Wookii]

Will you explain? I think if I leave the tap water to degas, CO2 content would decrease, and pH would rise, as a result. Am I missing here something?

Yes, you’re missing the train of the conversation which is about the video of the low tech tank in post #1147 and possible explanations as to how the person running the tanks was achieving apparent ‘high tech’ growth on a ‘low tech basis’. One of which was increased CO2 levels by daily water changes.

You also have to appreciate that whilst you might wait 24 hours for your water change water to degas, most don’t and go straight from tap to tank via hose or bucket.

 

[_Maq_]

But my question remains unanswered: Will you explain? I think if I leave the tap water to degas, CO2 content would decrease, and pH would rise, as a result.

 

[Gorillastomp]

Ita depends of your water supply, mine PH goes down if i let it sit on counter. That would mean my water supply is really low in dissolved co2. I use Well water.

 

[Wookii]

But my question remains unanswered: Will you explain? I think if I leave the tap water to degas, CO2 content would decrease, and pH would rise, as a result.

Explain what? Your statement is correct, but not relevant to what is being discussed?