Ph profile with pressurized co2

[Edvet]

I said 30 minutes earlier because there seemed to be another pH drop going on after lights on, and i believe it's best to start with optimal CO2 in the column at lights on, so just start a bit earlier.
The 4 hours i stole from Clive. Most hightech tanks light 6-8 hours. You can stop adding CO2 2 hours before lights end.
The whole "protection effect of CO2/Rubisco"against high light levels isn't fully understood as far as i know, though it is shown to be in effect.

 

[Puntius]

I said 30 minutes earlier because there seemed to be another pH drop going on after lights on, and i believe it's best to start with optimal CO2 in the column at lights on, so just start a bit earlier.
The 4 hours i stole from Clive. Most hightech tanks light 6-8 hours. You can stop adding CO2 2 hours before lights end.
The whole "protection effect of CO2/Rubisco"against high light levels isn't fully understood as far as i know, though it is shown to be in effect.

My lights are on from 14h00 till 22h00 9 hours where all the lights are on from 16h00. So full lighting phase for 5 1/2 hours.. So I will start co2 30 minutes earlier from tomorrow. Then my co2 will go off 2 hours before the lights out at 20h00. And airstone comes on at 21h30 and lights off by 22h15. Sure 1 hour is enough time for plants to warm up. So will be starting my 2 led tubes at 15h00 instead of 15h30 then 3rd tube will go on at 16h00..edited

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[Zeus.]

Thought plants respired all the time and produce CO2 even during the photoperiod. It's just at night any CO2 produced by the plants isn't used by the plants so hence it could tip the balance as it is the livestock blood [CO2] which drives respiration with the decreasing livestock's blood pH.
Long time since my advanced biology, I do now the ordinary level biology is well over simplified hence they teach photosynthesis during the day and respiration at night. is not until degree level that it all makes sense with those Eureka moments, well it was for me.

Edit- did a post just disappear ? As the above post was done after reading it.

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[Puntius]

Thought plants respired all the time and produce CO2 even during the photoperiod. It's just at night any CO2 produced by the plants isn't used by the plants so hence it could tip the balance as it is the livestock blood [CO2] which drives respiration with the decreasing livestock's blood pH.
Long time since my advanced biology, I do now the ordinary level biology is well over simplified hence they teach photosynthesis during the day and respiration at night. is not until degree level that it all makes sense with those Eureka moments, well it was for me.

Edit- did a post just disappear ? As the above post was done after reading it.

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Probably updated at the same time

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[Zeus.]

Probably updated at the same time

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Yep, mobile phones suck esp with intermittent WIFi no missing posts, I should of quoted the post OFC

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[Puntius]

Yep, mobile phones suck esp with intermittent WIFi no missing posts, I should of quoted the post OFC

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Yeah much better doing it like that sometimes. Yes intermittent wifi causes mishaps lol...

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[dw1305]

Hi all,

It's just at night any CO2 produced by the plants isn't used by the plants

Pretty much.

There is a complication in that a few aquatic plants (Isoetes, Sagittaria) use <"CAM photosynthesis">, and there maybe others with <"more flexible photosynthetic pathways"> than had been suggested.

Ottelia alismoides is a constitutive C4 plant and bicarbonate user, and has facultative crassulacean acid metabolism(CAM) at low CO2.......

I don't think that CO2 builds up in the lacunae and air spaces of the plant the way that oxygen does (a lot of the oxygen used for respiration outside of the photoperiod is derived from this internal storage (this is referenced on p. 6 of <"Ecology of the Planted Aquarium">)). The reason for this is that CO2 is much more soluble than oxygen and will tend to diffuse into the tank water.

cheers Darrel

 

[Edvet]

( I thought CAM plants are from dry arid areas only?)

 

[dw1305]

Hi all,

I thought CAM plants are from dry arid areas only?

You would expect that, but because it works as a CO2 concentrating mechanism it looks like it is useful to plants from CO2 limited areas (submerged aquatics). My suspicion would be that if people start looking they will find that a lot more aquatic plants have unusual photosynthetic pathways.

This is from the Pedersen & Colman paper (linked above).

CAM photosynthesis in terrestrial plant is thought to have evolved as a trait to conserve water and is thus particularly frequent among desert plants. CAM is also present in some aquatic plants inhabiting freshwater lakes and temporary pools. Here, CAM is unimportant as a water-conserving feature and instead it is considered of adaptive importance in carbon limited environments where CO2 is stored as malate during the night and subsequently released during the day and fixed in the normal Calvin cycle. As a consequence of extensive underwater photosynthesis, CO2 drops to very low concentration during the afternoon in vegetation-rich temporary pools....

cheers Darrel

 

[ceg4048]

Yes, agree with Darrel. There are quite a few aquatic species which evolved in CO2 poor waters or where CO2 concentration is higher at night.
I believe Vallis and Sagittaria are typical examples of CAM type plants.

Regarding the question of why it's a good idea to use less light at the beginning of the the photoperiod, the answer is simply that plants have a complex photosynthetic system and it takes time for everything to "warm up". Ramping up the light (starting low and increasing to high gradually) as opposed to bombarding them with full light just makes it easier for them to deal with the light.

Most of the problems we have with algae and poor performance in high tech tanks actually occur at the beginning of the photoperiod. Algae have very simple and efficient photosynthetic pathways and they can deal with strong lighting poor CO2 very easily. After about 4-5 hours the plants have pretty much accumulated the CO2 they need for the day, so the second half of the photoperiod is not nearly as important as the first half.

Cheers,

 

[Puntius]

Wow dude @ceg4048 thanks for your valued input. I changed my setup like this now.

Co2 start at 11h45 first light on at 14h00 then my 2nd stage lights 2 led tubes at 15h00 then lastly my one other tube around 15h45. Co2 on till 20h00 then. Airpump starts at 21h30. 2nd and 3rd tubes go off at between 21h30 and 21h40. Then last tube off at 22h15. Airpump then runs till 10 am where by that time all the co2 de gassed out.

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