Low Tech Fertiliser Dosing. Whats your technique?

[dw1305]

Hi all,

So, the question is, whether fish and microbes provide them more CO2 than oxygenation? @Wookii took for granted that oxygenation makes the water saturated with CO2 as much as possible. While I believe that this is not the case, except in the afternoon, perhaps.

I don't understand where this going.

Plants are net CO2 consumers, it isn't a suggestion or a hypothesis. The <"oxygen we breathe">, <"fossil fuels we burn"> and <"the steel we use"> were entirely created from the difference between the CO2 consumed and oxygen evolved during photosynthesis.

@Geoffrey Rea <"measured dissolved oxygen over a 24 hour period"> in his high tech tank, with some surprising findings.

I don't think any-one is arguing that <"dissolved oxygen isn't important">, I'm certainly not, in fact quite the opposite.

The reason for all this is that the prime metric we are interested in is dissolved oxygen, and nearly everything else is just "froth". We want the biological filtration media to be fully oxygenated (for the oxygen supply to exceed the oxygen demand). In the case of a planted tank, with your filter, it is going to be quite difficult to arrive at a situation where you have de-oxygenated media.

We have a thread <"maximising dissolved O2"> and another on <"maximising CO2 in a low tech tank">.

Personally I like some <"laminar flow"> (and <"direct aeration">) to replenish the <"levels of dissolved gases">. As general rule as the bioload get larger the gas exchange surface area <"also needs to gets larger">, this is to both outgas CO2 and replenish dissolved oxygen.

If we measure the <"diel variations in pH"> it gives you a pretty good indication of the CO2:O2 balance.

cheers Darrel

 

[_Maq_]

---

@_Maq_ you seem like an educated guy, other than being argumentative and splitting hairs, perhaps you could show us the fruits of your labour's.

I for one think I can attain some knowledge from you, but you need to show us your onions 😀

Okay. I'll make my introduction. Give me a few days.

 

[_Maq_]

I don't understand where this going.

Plants are net CO2 consumers, it isn't a suggestion or a hypothesis.

Plants are net CO2 consumers (as long as things go well) but our tanks not necessarily so. CO2 content in low-tech tanks is quite often higher than 0.5 mg/L. I think microbial respiration is the most important source of CO2, while surface movement / aeration works as a safety tool ensuring that CO2 never falls to zero.
In any case, I aerate to increase oxygen, not CO2. Oxygen is my prime concern. Lack of oxygen kills almost instantly, while lack of carbon dioxide does not.

 

[dw1305]

Hi all,

In any case, I aerate to increase oxygen, not CO2. Oxygen is my prime concern. Lack of oxygen kills almost instantly, while lack of carbon dioxide does not.

So do I, I'm really not to bothered about CO2 either, dissolved oxygen is the metric that matters <"How much does light effect the growth of "beneficial" bacteria?">.

while surface movement / aeration works as a safety tool ensuring that CO2 never falls to zero.

Agreed again. We have a thread - <"Maxing CO2 in Low Techs">.

I think microbial respiration is the most important source of CO2

There is no real way of knowing, there are just too many variables. It would certainly be true in wastewater treatment, where one of the problems is outgassing the CO2 rapidly enough to avoid pH depression etc. <"https://dspace.lib.cranfield.ac.uk/...and_nutrient_removal_from_wastewater-2019.pdf">.

Plants are net CO2 consumers (as long as things go well) but our tanks not necessarily so.

Plants are always:

• net carbon dioxide (CO2) consumers and
• net oxygen (O2)producers, until <"they die">.

For every molecule of CO2 incorporated a molecule of oxygen is evolved <"File:Photosynthesis equation.svg - Wikimedia Commons">.

The carbon portion of plant biomass is the sum of that difference, there is no way around that, it is the single fact that makes <"aerobic life possible">.

Plants are net CO2 consumers, it isn't a suggestion or a hypothesis. The <"oxygen we breathe">, <"fossil fuels we burn"> and <"the steel we use"> were entirely created from the difference between the CO2 consumed and oxygen evolved during photosynthesis.

cheers Darrel

 

[_Maq_]

there is no way around that, it is the single fact that makes <"aerobic life possible">.

You're correct, of course, in general terms.
Yet plants also respire to utilize the sugar gained during photosynthesis. There are occurrences when R/P > 1. Only temporarily, of course, because while this happens, the plant is heading toward death.