Yes the update is ready, just need some time to sanitize the file to make it user-ready and double check a few things because there has been some non-trivial changes. I have added the dKH of ADA Brighty K.
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Plants using bicarbonates for photosynthesis?
- Thread starter Ullalaaqua
- Start date
Ullalaaqua
Member
Thank you for the reply! This was the closest answer to the thing I’m trying to ask 😄If we take the label at its word, Brighty K is potassium oxide (K2O). K2O can be derived from potassium carbonate (K2CO3) by thermal decomposition but isn't the same as potassium carbonate. Adding K2O to water causes an immediate reaction (K2O + H2O → 2KOH) where the KOH dissociates into K+ (this is the potassium fertiliser component) and OH- which is the hydroxide anion, a very powerful base "strongly alkaline" (will raise pH) just as the label indicates. This is probably what Brighty K is... a solution of potassium hydroxide, whereas 'Neutral K' seems to be a solution of potassium chloride.
What happens to the hydroxide? You're injecting CO2 (and there is CO2 in the air) which will react with the hydroxide to form bicarbonate. Overall: KOH + CO2 →KHCO3. So you lose a little of your CO2, the pH you raised with the hydroxide comes back down (as the label states), and you increase the carbonate hardness (dKH) of your tank. More info on the reaction:
What are the products of KOH(s) + CO_2(g)? | Socratic
"KOH"_text((aq]) + "CO"_text(2(g]) -> "KHCO"_text(3(aq]) Potassium hydroxide, "KOH", will react with carbon dioxide, "CO"_2, to form potassium bicarbonate, "KHCO"_3, and water. The balanced chemical equation for this reaction looks like this "KOH"_text((aq]) + "CO"_text(2(g]) ->...socratic.org
This leaves open the question of whether you actually want to increase the carbonate hardness of your tank while you're adding potassium...
My point is not wanting to increase the carbonate hardness but to understand the chemical reaction behind this possible photosynthesis with bicarbonates and if these fertilizers that rise kh (for examble ADA Brighty K) could have been the thing that made that strong photosynthesis happen in my lowtech tank in the first place.
Why I want to know? I’m just curious about stuff like this 😁
Ullalaaqua
Member
Thank you! More pieces to the buzzle 🤩
Staghorn: has been a ”problem” in this tank. I managed to get it under control, but not complitely gone. I just had Crystal shrimp shrimplets, so I’ve been extra careful with too sudden changes even when experimenting with this 🙂 And I haven’t done spot treatment to the algae after I noticed the shrimplets eighter.
So the Staghorn has been there before I noticed pearling. Pearling happened first time after adding potassium that I know raise kh (I swiched from ADA Neutral Brighty K to ADA Brighty K.
To your question: after I stopped adding CO2 the plants came alive. Growth is slower than with CO2, but plants are stronger and fuller somehow. I’ve trimmed the rotalas once in this time.
Just incredible - I know ADA ferts are overpriced, but I didn’t realise Brighty K is just a very dilute K2CO3 based KH booster. That’s daylight robbery.
I wonder why they choose to use that rather than K2SO4. If memory serves, Brighty K is ADA’s first stage fert in their pre-prescribed regime, so is it perhaps to help buffer the declining KH due the organic acids released from the Amazonia?
Oldguy
Member
Total agree with @ sparkyweasel . The convention with fertilizes is to show key ingredients in a standard format so that one brand can be compared to another.
Potassium is not there as K2O and Phosphorus is not there as P2O5, both far too reactive. However it does enable comparisons to be made and actual formulations to be hidden.
Lovely pics @ Ullaaaqua.
Have used sodium bicarbonate solution and a desk lamp on Canadian Pondweed to demonstrate photosynthesis, easy to collect oxygen but hard on the plant.
Potassium bicarbonate would be a better choice than the carbonate, less effect on pH and it dissociates to the hydrogen carbonate ion which some plants use as a carbon source.
These plants are hard-water species because in natural waters the bicarbonate will be from calcium which often forms a white deposit on the plant leaves.
I mix my own aquarium ferts, so cheap compared with shop products and I like the nostalgia of having a 'chemistry set' so unfortunately cannot comment on over the counter products.
Happy fish tanks.
Sammy I
Member
K2SO4 has lower solubility level than the others i think? Could also be a depleting KH thing as you have suggested.
Thats makes some sense esp having come across a K2O% for many products when doing the IFC calculator, suppose its just like many quote N% in the analysis when the Nitrogen is a compound. We have done a similar approach for the comparison of Ammonium and Urea salts so we can compare the potential NO3 ppms for a given dose, obviously the biological pathways haven't taken place when we dose the salt/fert and we are assuming they will with a mature tank/filter. With Ammonium and Urea fert dosing I am a fan of dosing very lean doses very frequently (100 times a week with AIO) to allow these pathways to take place and migrate the potential toxic effects of using Ammonium/Urea as a source of Nitrogen.
K2CO3 solubility is pretty good at 20 degrees from the data we have on the IFC Calculator
Hi all,
cheers Darrel
They are probably oxygen. This (school) <"photosynthesis practical"> works much more efficiently with added KHCO3 (or <"NaHCO3">).
cheers Darrel
Yes, even though it was a very basic experiment the after about 10mins the explanation about the aerenchyma as the transport vessels for gases from plant to root and the fact they said adding xCO3 to the water helps increase the O2 produced for the students. Does strongly suggest adding CO3 helps increase O2 production
How much light intensity do you have? Intense light will triggers pearling of O2 with or without CO2 injection. I rarely observed pealing in my high tech medium light tank, but pearling occurs in my zero tech shrimp bowl every afternoon when sunlight hit. CO2 is stripped to 0.1 ppm by photosynthesis at the peak of sunlight, yet the growth rate of Lugwidgia is near zero due to CO2 limitation.
I don’t think you have any hardwarer plant such as Vals that is capable of splitting carbonate, and splitting carbonate is an inter cellular reaction and you won’t observe CO2 pearling but precipitation of white calcium mineral. CO2 has high solubility and pearling CO2 is much rarer than pearling O2, CH4 and N2.
Staghorn belongs to red algae as BBA, and can be eliminated effectively by excel and/or peroxide. But since you have crystal shrimp reproducing, dosing either can impact their reproduction, though adult shrimp can tolerate excel within recommended dosage. I have dosed excel many times to my cherry shrimp bowl with no death observed, The safest way to treat staghorn is to spray peroxide to exposed plants when you lower the water level during water change.
I don’t think you have any hardwarer plant such as Vals that is capable of splitting carbonate, and splitting carbonate is an inter cellular reaction and you won’t observe CO2 pearling but precipitation of white calcium mineral. CO2 has high solubility and pearling CO2 is much rarer than pearling O2, CH4 and N2.
Staghorn belongs to red algae as BBA, and can be eliminated effectively by excel and/or peroxide. But since you have crystal shrimp reproducing, dosing either can impact their reproduction, though adult shrimp can tolerate excel within recommended dosage. I have dosed excel many times to my cherry shrimp bowl with no death observed, The safest way to treat staghorn is to spray peroxide to exposed plants when you lower the water level during water change.
Ullalaaqua
Member
@tiger15
I don’t have the exact PAR numbers to give you about the light intensity. But they are at 100% around 10 hours per day. The light is ONF flat nano.
Good point about the hardwater plants. This is why I was so buzzled to see rotala pearling and after my friend gave me a tip about plants using bicarbonates for photosynthesis I wanted to look into that. There has been really good information in this thread about all the posibilities and then some 😄 This forum is amazing!
The Staghorn is a pain and I had good results with spot dosing excel before I noticed one of the crystals carrying eggs. So I haven’t done anything about it since. Some say that NPK dosing would help getting rid of it, but I desided to just try and focus on the plant health and keeping the tank balanced as it is. I still have the option to put CO2 back and running. But the crystals seem so much healthier without it and the tank seems well balanced recardless the Staghorn.
Maybe I’ll just let the shrimplets grow and see if regular maintenance and dosing will eventually make Staghorn go away. You think carbonates give red algaes more boost on growing? I have a faint memory they might like higher kh levels more.
I don’t have the exact PAR numbers to give you about the light intensity. But they are at 100% around 10 hours per day. The light is ONF flat nano.
Good point about the hardwater plants. This is why I was so buzzled to see rotala pearling and after my friend gave me a tip about plants using bicarbonates for photosynthesis I wanted to look into that. There has been really good information in this thread about all the posibilities and then some 😄 This forum is amazing!
The Staghorn is a pain and I had good results with spot dosing excel before I noticed one of the crystals carrying eggs. So I haven’t done anything about it since. Some say that NPK dosing would help getting rid of it, but I desided to just try and focus on the plant health and keeping the tank balanced as it is. I still have the option to put CO2 back and running. But the crystals seem so much healthier without it and the tank seems well balanced recardless the Staghorn.
Maybe I’ll just let the shrimplets grow and see if regular maintenance and dosing will eventually make Staghorn go away. You think carbonates give red algaes more boost on growing? I have a faint memory they might like higher kh levels more.
Ullalaaqua
Member
Have you found out your light intensity. I bet you have high light judging from the vivid color of your Rotala. Mine don’t get as red as yours under medium light.