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Do you take the 1 pH drop from completely degassed water or from just before CO2 turns on?

I fully understand the need for more complex multiple CO2 regulator/computer control etc for large tanks like Zeus 500 litre and Josh's observations may well be highly useful to solving the problems found in larger setups.

For a 120p tank or smaller, a single inline diffuser into a Oase Biomaster is sufficient as evidenced by Dennis Wong's tank. Dennis Wong, like Tom Barr, has a constant stream of visitors visiting him and his tanks (including Vin Kutty when he visited Singapore) so in that sense his setup has been verified (he's not hiding some secret equipment he's not telling you about). Seeing some handphone photos of Dennis' tank by visitors, we also know he's not photoshopping his tank pics (same for Tom Barr's tanks).

By keeping the technique simple, consistent and reproducible, we will be able to increase the popularity of the hobby.
There is plenty of evidence that the technique that Dennis Wong is using can be consistently reproduced with a normal CO2 setup. He recommends a ramp-up of 2-3h, a 1 pH drop to a 20-35 ppm target with stabilization through gaseous exchange. This is the goal that many try to achieve.

On the other hand, Barr claims that his technique manages to reach a stable level of CO2 after ~30 min using high injection rate, strong light, and gaseous exchange. Are there examples of tanks apart from Barr's that manage to replicate this result while keeping CO2 and O2 levels within what are considered acceptable thresholds?
 
On the other hand, Barr claims that his technique manages to reach a stable level of CO2 after ~30 min using high injection rate, strong light, and gaseous exchange. Are there examples of tanks apart from Barr's that manage to replicate this result while keeping CO2 and O2 levels within what are considered acceptable thresholds?


I do wonder how much the trickle filter has an impact on TBarrs ability to achieve this. Seen his tanks so wouldn’t dispute that it is possible.

I don’t know how many tanks he uses these on but I understand he’s not a fan of canisters.

I believe that a wet/dry trickle filter has a significant capacity for gaseous exchange so potentially off gassing of Co2 would be rapid and loss of O2 minimised due to the significant exposure to atmosphere using this method?

He also generally has high biomass which would be creating excess 02 in the tank under high light.

Maybe this filtration/gaseous exchange method combined with high biomass (high light) is the trick to maintaining equilibrium at reasonable Co2 levels with high injection rates?

I don’t think he’s too shy of going over 30ppm either but he doesn’t appear to gas his fish.

This method, assuming effective, may be another ‘road to Rome’ but should it perhaps come with the caveat of ‘use with caution’. I’m personally inclined to feel that high light/high energy is also synonymous with rapid failure if things become unbalanced, whereas a lower/slower system has inherently more wriggle room!

Would also be interested in any other examples!
 
On the other hand, Barr claims that his technique manages to reach a stable level of CO2 after ~30 min using high injection rate, strong light, and gaseous exchange. Are there examples of tanks apart from Barr's that manage to replicate this result while keeping CO2 and O2 levels within what are considered acceptable thresholds?
ADA, Felipe Olivera, Old school PPS-Pro followers, the list goes on. On this forum - you just have to look.

Barr isn't untouchable. The guy is curious and knows how to play by the rules.

I remember Barr's post - with the elephant nose extremely rare extremely sensitive fish ~ high co2 ppm. Go back to natural habitat and check the pH of that thing. He's not posting photos of hardwater or brackish Goby's for a reason. He plays by the rules.

Greggz and his Rainbows -- presumably higher KH needed for rainbows -- but he doses EI, high light, high CO2 -- with EI ferts in the column you have even more oxygen evolution .. the fish can adapt to the changes in osmotic pressure when there is enough of everything else in balance.

Dennis Wong - massive light, lean to moderate dosing -- less demand on CO2 ... less of a demand throughout the period -- less fluctuation. Pour a bottle of 3x EI into that tank and he's going to get algae - because the CO2 demand will fluctuate and stuff won't meet it. He will need to re-evaluate his injection rate. Barr and anyone dosing EI can't play that game -- unless you 1) turn down your lights or 2) crank your injection rate, reduce your ramp time, increase surface agitation and increase your lights.

Dutch tanks that are gorgeous that dose similar to EI - have to have high light and to compensate for the CO2 they pump into the system (otherwise the plants get leggy, large leaves, etc), they cannot afford to have long ramp up times (or the system will get gassed) - they need to compress it closer to lights on. And with such a fast drop, there is no need to have any ramp on your lights or before your lights for CO2

(yes, a beautiful 4 hour ramp up of your lights paired with a nice slow injection CO2 constantly matching the lights down down up up and then boom high light, everything gets going for 2-3 hours, then 4 hour ramp down while CO2 comes back ... this is nature -- it's tough to do it, very --- so we make the system as efficient as we can because we are faking it).
 
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ADA, Felipe Olivera, Old school PPS-Pro followers, the list goes on. On this forum - you just have to look.
Honestly, I am not sure where to look. There are plenty of examples using either two independent CO2 circuits or long (2-3h) ramp up periods. But I am not aware of examples using short ramp-up periods and high injection rates... The tank Filipe set up in his Green Aqua masterclass used a long CO2 ramp-up period. He describes the same technique in is vlog for a few of his home tanks. I never heard him advising high injection rates and short ramp up periods.

(...) Dennis Wong - massive light, lean to moderate dosing -- less demand on CO2 ... less of a demand throughout the period -- less fluctuation. Pour a bottle of 3x EI into that tank and he's going to get algae - because the CO2 demand will fluctuate and stuff won't meet it. He will need to re-evaluate his injection rate. Barr and anyone dosing EI can't play that game -- unless you turn down your lights or crank your injection rate, reduce your ramp time, increase surface agitation and increase your lights.
I do not know if the CO2 levels in Dennis' tanks would fluctuate or not. What I know is that there are several tank keepers that manage to keep successful tanks using EI and high lights and use the same CO2 technique that Dennis is using...

Dutch tanks that are gorgeous that dose similar to EI - have to have high light and to compensate for the CO2 they pump into the system (otherwise the plants get leggy, large leaves, etc), they cannot afford to have long ramp up times (or the system will get gassed) - they need to compress it closer to lights on.
If I understood you correctly, the reasoning is that in a high energy tank, CO2 equilibrium cannot be reached with a long ramp up period because CO2 injection will be unable to meet demand during the photoperiod. This means that in such tanks a stable CO2 level is only achievable with a short ramp up period and a high injection rate.

Are there specific examples of the techniques being used in such cases and of the the resulting CO2 and O2 levels at equilibrium?
 
Consider the entire turnover of your tank as a single pulse through the tank. Imagine you are in the first hour of the photoperiod and each wave is pretty consistent (since the injection is constantly topping it up). Then some species in front of you decide that it's time for them to really get the machinery going and they start sucking up more CO2 before it gets to you. You still have enough when it gets to you but then when the wave passes back to the injection site to refill the rate can't refill it back to the top (PLUS the injection site also offgasses right? -- so you are offgassing and then refilling but the offgas itself may not offgas BACK to atmospheric --- unless its wet/dry). So the next pass you get less from the refill. And this continues because all your buddies in front get their machinery going. So when you get your machinery going you can't keep up and end up deficient.

Now, suppose you had a higher offgas rate, then you need a higher injection and hence the likelihood of falling short of the refill is less. So you won't lose out, even if your buddies start first.

I think I’m almost there with this one but struggling a little with some of the concepts. This is kinda like being at school 😂 (I was a pain in the ear there too)

Query - assuming the above process, how does this differ from my current ‘usual’ method.

I know that I can reach a drop of 1ph by lights on so, for the sake of argument, let’s assume 30ppm. I am then also assuming a good level of equilibrium is achieved as I have a steady ph throughout photo period which would indicate that the 30ppm of Co2 remains in the water column and (with good distribution) is available to whatever plant wants it. If my Co2 injection level was not high enough to ‘top up’ the Co2 that had been used/lost whilst going through the tank, would this not correspond to fluctuations in ph that I would be able to measure?

If not, why not?

I get that your model is probably overly simplified for the sake of explanation but let’s say, the first 9 plants in the queue get their fill of Co2 so plant 10 has less available and, if the water is not fully topped up by injection rate, then on the next pass this issue is exacerbated resulting in diminishing returns and ultimately a deficiency. In this instance, would you not see an overall (measurable) drop in the Co2 in the tank? Surely the purpose of maintaining a steady 30ppm/ph drop is to ensure that an excess amount of Co2 is available throughout the tank at all times?

This is all mechanical. Light adds another piece - it gives the plant the opportunity to use the CO2. It means that you have that much more consumption buffer -- suppose that a needwheel turn gives 10 CO2 (whatever that means) and you have low light that can only absorb 1 CO2 ... then each turn will give you 9 surplus and that can be hard on fishies. Suppose now you turn the light up to absorb 8 CO2. Then mabe you make a few turns and it only goes up 6. It's easier - more room for error. It's terribly unrigorus but I think shares the intuition.

I think with this one, I’m almost asking the same question again. When measuring ph on a ph profile, are we not effectively measuring the ‘spare’ Co2? i.e the Co2 that is not being consumed by plants and not being off gassed! Surely we can’t measure the Co2 that is being used because it’s been used so it’s not there! Therefore as long as we are measuring 30ppm/1ph, this is the amount remaining in the water and so the gas impact would be the same on the fishies regardless?
 
Honestly, I am not sure where to look. There are plenty of examples using either two independent CO2 circuits or long (2-3h) ramp up periods. But I am not aware of examples using short ramp-up periods and high injection rates... The tank Filipe set up in his Green Aqua masterclass used a long CO2 ramp-up period. He describes the same technique in is vlog for a few of his home tanks. I never heard him advising high injection rates and short ramp up periods.


I do not know if the CO2 levels in Dennis' tanks would fluctuate or not. What I know is that there are several tank keepers that manage to keep successful tanks using EI and high lights and use the same CO2 technique that Dennis is using...


If I understood you correctly, the reasoning is that in a high energy tank, CO2 equilibrium cannot be reached with a long ramp up period because CO2 injection will be unable to meet demand during the photoperiod. This means that in such tanks a stable CO2 level is only achievable with a short ramp up period and a high injection rate.

Are there specific examples of the techniques being used in such cases and of the the resulting CO2 and O2 levels at equilibrium?
I'll dig and see if I can find some concrete stuff. Much of it I haven't bookmarked (kind of like that Barr post - I'd read the one you linked in the past ... probably a few times).
 
I think I’m almost there with this one but struggling a little with some of the concepts. This is kinda like being at school 😂 (I was a pain in the ear there too)

Query - assuming the above process, how does this differ from my current ‘usual’ method.

I know that I can reach a drop of 1ph by lights on so, for the sake of argument, let’s assume 30ppm. I am then also assuming a good level of equilibrium is achieved as I have a steady ph throughout photo period which would indicate that the 30ppm of Co2 remains in the water column and (with good distribution) is available to whatever plant wants it. If my Co2 injection level was not high enough to ‘top up’ the Co2 that had been used/lost whilst going through the tank, would this not correspond to fluctuations in ph that I would be able to measure?

If not, why not?

I get that your model is probably overly simplified for the sake of explanation but let’s say, the first 9 plants in the queue get their fill of Co2 so plant 10 has less available and, if the water is not fully topped up by injection rate, then on the next pass this issue is exacerbated resulting in diminishing returns and ultimately a deficiency. In this instance, would you not see an overall (measurable) drop in the Co2 in the tank? Surely the purpose of maintaining a steady 30ppm/ph drop is to ensure that an excess amount of Co2 is available throughout the tank at all times?



I think with this one, I’m almost asking the same question again. When measuring ph on a ph profile, are we not effectively measuring the ‘spare’ Co2? i.e the Co2 that is not being consumed by plants and not being off gassed! Surely we can’t measure the Co2 that is being used because it’s been used so it’s not there! Therefore as long as we are measuring 30ppm/1ph, this is the amount remaining in the water and so the gas impact would be the same on the fishies regardless?

You are spot on @KirstyF - this is the point I was trying to make to Josh yesterday - if we target and achieve a consistent level of CO2 in the water column, as measured by pH or drop checker in all areas of the tank, then all is left is correct distribution of that CO2 enriched water. If plant 10 becomes deficient it is not because the injection rate is not high enough, it is because the CO2 enriched water isn't being passed to its leaves quickly enough - its a distribution issue.
 
I do wonder how much the trickle filter has an impact on TBarrs ability to achieve this. Seen his tanks so wouldn’t dispute that it is possible.
I am also not disputing this. But if this technique is not reproduceable then it is simply irrelevant to the community! I would really like to know what is being done and what are the CO2 and O2 levels that result from it.

I don’t know how many tanks he uses these on but I understand he’s not a fan of canisters.
I believe that a wet/dry trickle filter has a significant capacity for gaseous exchange so potentially off gassing of Co2 would be rapid and loss of O2 minimised due to the significant exposure to atmosphere using this method?
He also generally has high biomass which would be creating excess 02 in the tank under high light.
There will be O2 loss through surface agitation in the tank because high CO2 tanks need high water flow. The higher the flow, the higher the O2 loss. A wet/dry filter or any other setup cannot selectively promote the loss of CO2 while keeping O2. Both gases would be lost.

Maybe this filtration/gaseous exchange method combined with high biomass (high light) is the trick to maintaining equilibrium at reasonable Co2 levels with high injection rates?
The issues is that high-energy, high biomass tanks with lower CO2 injection can reach at least the same O2 at equilibrium due to saturation of the water column. In the best case scenario, a tank with high injection will have more dissolved CO2 but no more O2 than tanks using lower injection rates. It will probably have less O2 since it will require more water circulation. IMO, if there are no examples of how to replicate this technique and of its results, then it makes no sense to discuss it.
 
I think I’m almost there with this one but struggling a little with some of the concepts. This is kinda like being at school 😂 (I was a pain in the ear there too)

Query - assuming the above process, how does this differ from my current ‘usual’ method.
It doesn't. That's the beauty. You are meeting the refresh rate of CO2 under your current system. You have minor exposure to CO2 during ramp time but whatever since the fish are fine. So why bother changing? Efficiency and stability. Algal blooms in nature are natures way of safeguarding stability. Algae show up to help restabilize save the life --> sequester nutrients. The plants are ok with it, they don't mind.

If you add a second light or increase your light, you will start to see adaptations. One benefit is that the system will start to cleanse because of uptake -- and the water will become crystal clear without purigen etc -- any lick of ammonia will be sequestered in plant matter. Oxygen evolution will increase -- O2 is the key to life. Diatoms don't need to be present at startup -- turn your lights up, favor photosynthesis and they go away. Oxygen allows higher order things to outcompete the brown protista.
I know that I can reach a drop of 1ph by lights on so, for the sake of argument, let’s assume 30ppm. I am then also assuming a good level of equilibrium is achieved as I have a steady ph throughout photo period which would indicate that the 30ppm of Co2 remains in the water column and (with good distribution) is available to whatever plant wants it. If my Co2 injection level was not high enough to ‘top up’ the Co2 that had been used/lost whilst going through the tank, would this not correspond to fluctuations in ph that I would be able to measure?

If not, why not?
I mean yes - but you need localized measurements etc. Also, fluctuations of the water aren't a bad thing -- I mean if the plant is "done" and doesn't need any more CO2 to continue photosynthesizing for the day, then it doesn't need anymore. If you have low enough injection rate and track pH, you can see the plants ~4 hours massively shift the pH up then it slowly comes back down. It's like they get their fill and fill up on CO2 in gas sacks -- it's like predicting what they will need for the rest of the photoperiod.

They take what they need, let the pH skyrocket, then let Rubisco go crazy (it functions better at higher pH) and let the bacterias work better (neutrophiles ~ ph 7) -- so they are almost giving the system what it needs to function after it has taken what it needs. If the system functions better, then we all win.

Fluctuation when demands aren't met is not good. Straight up, you get algae. And less efficient, the blacker it is. If it's extremely efficient then you need even more fluctuations - literally spin your needle wheel and spawn whatever algae you want.
I get that your model is probably overly simplified for the sake of explanation but let’s say, the first 9 plants in the queue get their fill of Co2 so plant 10 has less available and, if the water is not fully topped up by injection rate, then on the next pass this issue is exacerbated resulting in diminishing returns and ultimately a deficiency. In this instance, would you not see an overall (measurable) drop in the Co2 in the tank? Surely the purpose of maintaining a steady 30ppm/ph drop is to ensure that an excess amount of Co2 is available throughout the tank at all times?
I'd say yes. Stable pH isn't bad during photoperiod. In fact, if you try guess that beautiful balance I describe above, you will fail. It's too hard. So stability ends up being a result of efficiency. But low injection rate decreases stability since any nutrient fluctuation will mess with it. That's why EI works. It doesn't fluctuate nutrients, and with an inefficient system you turn down the lights to match a low injection rate.

But to make the system healthier, to chase plant forms etc, you need to chase different conditions. <-- always goal of the hobbyist at its forefront.
I think with this one, I’m almost asking the same question again. When measuring ph on a ph profile, are we not effectively measuring the ‘spare’ Co2? i.e the Co2 that is not being consumed by plants and not being off gassed! Surely we can’t measure the Co2 that is being used because it’s been used so it’s not there! Therefore as long as we are measuring 30ppm/1ph, this is the amount remaining in the water and so the gas impact would be the same on the fishies regardless?
Bingo. But it needn't be there in the first 5 minutes - I don't mean to be cheeky, but to try to get it there with several hours of ramp is an indicator in itself.

In higher KH, you likely need some ramp to allow that first 5 minutes to get what they need (because getting that CO2 with more salts requires more free CO2). But not at lower KH where CO2 acquisition is easier.
 
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It doesn't. That's the beauty. You are meeting the refresh rate of CO2 under your current system. You have minor exposure to CO2 during ramp time but whatever since the fish are fine. So why bother changing? Efficiency and stability. Algal blooms in nature are natures way of safeguarding stability. Algae show up to help restabilize save the life --> sequester nutrients. The plants are ok with it, they don't mind.

If you add a second light or increase your light, you will start to see adaptations. One benefit is that the system will start to cleanse because of uptake -- and the water will become crystal clear without purigen etc -- any lick of ammonia will be sequestered in plant matter. Oxygen evolution will increase -- O2 is the key to life. Diatoms don't need to be present at startup -- turn your lights up, favor photosynthesis and they go away. Oxygen allows higher order things to outcompete the brown protista.

I mean yes - but you need localized measurements etc. Also, fluctuations of the water aren't a bad thing -- I mean if the plant is "done" and doesn't need any more CO2 to continue photosynthesizing for the day, then it doesn't need anymore. If you have low enough injection rate and track pH, you can see the plants ~4 hours massively shift the pH up then it slowly comes back down. It's like they get their fill and fill up on CO2 in gas sacks -- it's like predicting what they will need for the rest of the photoperiod.

They take what they need, let the pH skyrocket, then let Rubisco go crazy (it functions better at higher pH) and let the bacterias work better (neutrophiles ~ ph 7) -- so they are almost giving the system what it needs to function after it has taken what it needs. If the system functions better, then we all win.

Fluctuation when demands aren't met is not good. Straight up, you get algae. And less efficient, the blacker it is. If it's extremely efficient then you need even more fluctuations - literally spin your needle wheel and spawn whatever algae you want.

I'd say yes. Stable pH isn't bad during photoperiod. In fact, if you try guess that beautiful balance I describe above, you will fail. It's too hard. So stability ends up being a result of efficiency. But low injection rate decreases stability since any nutrient fluctuation will mess with it. That's why EI works. It doesn't fluctuate nutrients, and with an inefficient system you turn down the lights to match a low injection rate.

But to make the system healthier, to chase plant forms etc, you need to chase different conditions. <-- always goal of the hobbyist at its forefront.

Bingo. But it needn't be there in the first 5 minutes - I don't mean to be cheeky, but to try to get it there with several hours of ramp is an indicator in itself.

In higher KH, you likely need some ramp to allow that first 5 minutes to get what they need (because getting that CO2 with more salts requires more free CO2). But not at lower KH where CO2 acquisition is easier.
Now I am bit lost by your answer :) Concrete questions behind this "short ramp up" technique:
  • What is the duration of the ramp up period and the CO2 ppm and pH drop immediately before lights on?
  • What CO2 ppm is expected during the photoperiod?
  • Are CO2 levels supposed to be stable or are they supposed to fluctuate during the photoperiod?
  • How is equilibrium maintained?

If we consider the "long ramp up technique", the answers would be something like
  • What is the duration of the ramp up period and the CO2 ppm and pH drop immediately before lights on?
    • 2-3 hours to achieve a ~1 pH drop to a target of ~30ppm
  • What CO2 ppm is expected during the photoperiod?
    • The same level as immediately before lights on, i.e. ~30 ppm.
  • Are CO2 levels supposed to be stable or are they supposed to fluctuate during the photoperiod?
    • Stable (e.g. within a ~10% range of the target); can be indirectly measured via pH profile
  • How is equilibrium maintained?
    • gas exchange through surface agitation
    • high flow/circulation to distribute O2 and CO2
    • CO2 ramp-up period set up as a function of CO2 demand (lights, plant mass, water flow, ...) and CO2 input (tank size, injection method, ...)
 
Now I am bit lost by your answer :)
hehe - whoops!
Concrete questions behind this "short ramp up" technique:
  • What is the duration of the ramp up period and the CO2 ppm and pH drop immediately before lights on?
Can be 0 minutes - when you consider the efficiency piece any ramp short changes how much you can pump in since the plants won't be able to keep up (and keep livestock safe) with a high inejction if it gets a head start. CO2 ppm is going to be dependent on respiration of the plants overnight: if there is high metabolism and the sugar to maintain it, then it is very possible to have green or light blue drop checker at lights on - but it's contingent on lots of factors. If you have lots of surface agitation, then closer to potentially close to that magic 3 ppm but probably not since we often need to run a bubbler in our tank water to find the degassed pH instead of just taking a reading before CO2 turns on.
  • What CO2 ppm is expected during the photoperiod?
I don't know. It will be unique to plant choice, ferts, tank conditions etc. If you have a tank full of softwater plants, it needs to be higher. If you have some "easier or medium" plants then you can get away with less.
  • Are CO2 levels supposed to be stable or are they supposed to fluctuate during the photoperiod?
Assuming that stable means they stay the same the whole period start to finish.

They need not be "stable" - the plant just needs enough to keep up. Stability isn't bad (and it will guarantee optimum CO2 at lights on etc). But is not a neccesary condition. The pH shouldn't fluctuate up and down like with yeast reactor - this is no good. But big drop, stable, cut the gas, let it rise back up -- this is fine. Clive did it.
  • How is equilibrium maintained?
Same.
If we consider the "long ramp up technique", the answers would be something like
  • What is the duration of the ramp up period and the CO2 ppm and pH drop immediately before lights on?
    • 2-3 hours to achieve a ~1 pH drop to a target of ~30ppm
  • What CO2 ppm is expected during the photoperiod?
    • The same level as immediately before lights on, i.e. ~30 ppm.
  • Are CO2 levels supposed to be stable or are they supposed to fluctuate during the photoperiod?
    • Stable (e.g. within a ~10% range of the target); can be indirectly measured via pH profile
  • How is equilibrium maintained?
    • gas exchange through surface agitation
    • high flow/circulation to distribute O2 and CO2
    • CO2 ramp-up period set up as a function of CO2 demand (lights, plant mass, water flow, ...) and CO2 input (tank size, injection method, ...)
Love it.

There really isn't much of a difference except the concept of lights on co2 (but with shorter ramp it doesn't matter since it gets there so fast). Does it need to be "at 30 ppm" at lights on or not. Leidbig says no. Don't misinterpret lights on CO2 is very important -- the plant cares a lot about lights on CO2. But if you have high inj. rate (paired with proper turnover, flow, etc), it is getting what it needs.

I think the starter of this was because I said light helps you dial in co2. With higher light, you can't have long ramp - it won't work because the CO2 inj. rate required over photoperiod will accumulate too fast if it gets a headstart.

I mean Dennis Wong uses high light and ramps ... maybe he doesn't actually need to (there is no harm to plants in having CO2 during lights off). Singapore water is super soft. But if he made the suggestion of no ramp, then anyone with higher KH water may fail with his line of fertilizer etc.

ADA says the system works with soft water - Amano advised lights and CO2 like Tom Barr.


Enjoying chatting about this -- making me do some good thinking :).
 
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I’m enjoying it too!

I think the starter of this was because I said light helps you dial in co2. With higher light, you can't have long ramp - it won't work because the CO2 inj. rate required over photoperiod will accumulate too fast if it gets a headstart.

Ok - I’m going to flip this one on its head, (Kind of) so bear with me. I’m still stuck on mechanics rather than benefits.

Can we agree for the purpose of this example, that light drives Co2 demand. I know other things may also contribute but let’s leave them to one side for the moment.

On that basis, light dictates plant uptake and subsequently, how much Co2 is required during photoperiod to meet that demand.

The higher the light, the more uptake, the more Co2 required.

The more Co2 we inject prior to lights on (should we choose to) the quicker we hit our desired drop and the shorter the ramp up period is.

In addition to the above, the tank has a certain amount of off gassing. The amount that is off gassed is dictated by the level of water movement/off gassing method used. (I’m guessing the amount of Co2 in the water may also impact the amount of off-gassing but I’m setting that aside too)

So the more off gassing we have, the more gas we need to maintain our Co2 level.

If we therefore combine high light and high off gassing we would need high Co2 and subsequently the ramp up period would naturally be reduced.

Regardless of this, once we have balanced our input (Co2 injection) with our output (uptake and off gassing) equilibrium is achieved.

Therefore, with the above method, the uptake demand and the off gassing method dictates the ramp up period, whatever that may be.

So is it a fact that you can’t have long ramp with high light or simply a case that, as a result of high light, ramp up periods are naturally shorter (not necessarily super short, just shorter)

I currently run lower light (new tank) and it takes 3.5 hrs of Co2 ramp up to hit 30ppm, in my 700ltr tank, by lights on. (I ramp the lights for just 30mins for the happiness of my fishies) How much higher would my light/Co2 demand have to be to naturally reduce my ramp to 30mins I wonder?

My feeling is that regardless of how much light I ran, uptake would never increase to a point where I would have to inject the level of Co2 required to get to 30ppm in 30mins.

I’m currently running more bubbles than I can count into two reactors, let’s say 20bps between them, for arguments sake. I’m sure it’s not linear but how would I hit that 30mins ‘target’? 60bps? 90bps? Or do I just lay the bottle in the tank and open it? 😳😂

Joking but you know what I mean!

Also

With your method, you eliminate ramp up by dictating high Co2 (rapid injection) you run high light but have ‘unlimited’ Co2 so no deficiency but you must surely also have to have a high level of off-gassing to ensure that Co2 levels don’t just keep increasing. How else could you guarantee that your plants use the amount of Co2 you are throwing at them by ‘dictating’ a 30 min max ramp up. They will only use what they need, the rest has to go somewhere?
 
So is it a fact that you can’t have long ramp with high light or simply a case that, as a result of high light, ramp up periods are naturally shorter (not necessarily super short, just shorter)

No, ramp up times are unlikely to be significantly changed. You increase the injection rate if you are aiming for a higher absolute CO2 level, but the rate increase is unlikely to be large if you are already hitting 30ppm consistently. Regardless, you increase the injection rate, it still takes a similar amount of time to reach your new higher CO2 target.

As @arcturus has pointed out above, you can only significantly increase the rate of injection by running a dual injection system, and by changing the rate of injection through the photo period (very high at the start, reduced for the remainder).
 
as a result of high light, ramp up periods are naturally shorter (not necessarily super short, just shorter)
I'd say "yes". Depends on the relative light increase. Double it and your old inj. rate won't keep up. As a result, need higher inj. rate. And the same ramp up time will gas the livestock.
I currently run lower light (new tank) and it takes 3.5 hrs of Co2 ramp up to hit 30ppm, in my 700ltr tank, by lights on. (I ramp the lights for just 30mins for the happiness of my fishies) How much higher would my light/Co2 demand have to be to naturally reduce my ramp to 30mins I wonder?
Great question.
My feeling is that regardless of how much light I ran, uptake would never increase to a point where I would have to inject the level of Co2 required to get to 30ppm in 30mins.
Valid. Might also need gas exchange to go up :).
I’m currently running more bubbles than I can count into two reactors, let’s say 20bps between them, for arguments sake. I’m sure it’s not linear but how would I hit that 30mins ‘target’? 60bps? 90bps? Or do I just lay the bottle in the tank and open it? 😳😂

Joking but you know what I mean!
hah!
Also

With your method, you eliminate ramp up by dictating high Co2 (rapid injection) you run high light but have ‘unlimited’ Co2 so no deficiency but you must surely also have to have a high level of off-gassing to ensure that Co2 levels don’t just keep increasing.
Yep!

Having off-gas buffer as lots is also easier on us as hobbyist - since a lot of your needle wheel adjustments is "off-gassed".
 
No, ramp up times are unlikely to be significantly changed. You increase the injection rate if you are aiming for a higher absolute CO2 level, but the rate increase is unlikely to be large if you are already hitting 30ppm consistently. Regardless, you increase the injection rate, it still takes a similar amount of time to reach your new higher CO2 target.

As @arcturus has pointed out above, you can only significantly increase the rate of injection by running a dual injection system, and by changing the rate of injection through the photo period (very high at the start, reduced for the remainder).

I’m kinda with you here at the moment. I’m just a bit like a terrier at a bone because there has to be an answer.

I guess if you tripled ur BPS (arbitrary number) you would hit 30ppm sooner? but the problem is, the ppm would then just keep climbing. My question to @JoshP12 is how would you then use or get rid of that Co2 to stop it from keep climbing? and whilst some extra uptake from higher light plants may use some Co2, it wouldn’t take up enough Co2 to allow that ‘tripling’ of BPS.
IMO of course 😊

Having said that TBarr, who is the example being used in the most part, does claim Co2 ramp up of less than an hr in some good size tanks, and I don’t think he’s fibbing, so he’s doing it somehow and not with a dual injection system.

Maybe the answer is not about uptake or off gassing, maybe the likes of TBarr are just super efficient at getting the Co2 to the tank in the first place?

Anyone else use a needle wheel and sump pump to inject?? 🤔😂
 
@KirstyF As @Wookii stated, further increasing the injection rate would lead to a higher CO2 ppm. The equilibrium point will result from CO2 output (gas exchange + plant intake) and CO2 injection/input. If the starting point is a low light setup, then we have some room to nudge the equilibrium point by increasing the lights and therefore CO2 intake by the plants. But if the tank is already using strong lights then there is virtually no margin to offset the CO2.

If a tank that uses strong lights needs 2-3 hours to reach for example 30ppm at a given injection rate, and if CO2 concentration is stable throughout the photoperiod this means that CO2 is not limiting for the current light input (if it were, then CO2 levels would drop). If the level is stable it means that CO2 demand is in equilibrium with CO2 input. Further increasing CO2 injection will then simply increase CO2 concentration without any benefits (it only has benefits if the light input is also further increased, but such reasoning does not apply if the tank is already using the desired amount of light). Or am I missing something here?
 
because there has to be an answer.
Unfortunately not kirsty. Different strokes for different folks would be the correct and absolute answer.
There's 2 systems at work here.

The skilled observant edge cutting guy's that push the boundaries of our knowledge. We learn lots but they gas fish with CO2. Clive admits it, suspect barr has done it in the past.

The newbies that take it nice and slow (big ramp ups, low injection rate)... pros less likely to gas fish... cons may have unhealthy plants...

Newbies also gas fish, usually when they chase higher CO2 levels.

I would never push the boundaries on CO2 because my fish are paramount, others experiment, suspect their plants are the important bit 😉

Just my musings, cary on with the discussion...

Edit: their isn't a right answer because Everyone is right ...
 
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@KirstyF As @Wookii stated, further increasing the injection rate would lead to a higher CO2 ppm. The equilibrium point will result from CO2 output (gas exchange + plant intake) and CO2 injection/input. If the starting point is a low light setup, then we have some room to nudge the equilibrium point by increasing the lights and therefore CO2 intake by the plants. But if the tank is already using strong lights then there is virtually no margin to offset the CO2.

If a tank that uses strong lights needs 2-3 hours to reach for example 30ppm at a given injection rate, and if CO2 concentration is stable throughout the photoperiod this means that CO2 is not limiting for the current light input (if it were, then CO2 levels would drop). If the level is stable it means that CO2 demand is in equilibrium with CO2 input. Further increasing CO2 injection will then simply increase CO2 concentration without any benefits (it only has benefits if the light input is also further increased, but such reasoning does not apply if the tank is already using the desired amount of light). Or am I missing something here?

Well, if you are missing something. I certainly don’t know what it is.

This all makes complete sense to me but I still can’t really figure out how you get a 1ph drop on a reasonable sized tank in less than an hour. (Without dual Co2) 😩

My next theory is magic Co2, fairy dust and unicorns.

Plantbrain, come save me from my madness. 🤣

I can, however, see and would agree @JoshP12 with some of your points about the benefits of running a tank at high light. I think that’s a personal choice (possibly based on how risk averse you are!) and not something I’d necessarily recommend to a novice. It is, however, something that I would like to try in the future. Tons of light, tons of Co2, a stack of ferts and have a wee play. This would, however, first be on a tank that I didn’t mind accidentally murdering and with no fauna. After all, you learn more from the mistakes you make than you ever do from getting it right first time, and how fab would it be to achieve great results whilst pushing those boundary’s.

Right now, like a well behaved (and risk averse) newbie, I think I’ll continue to take things slow and steady. My light levels will increase some over time but I won’t be getting the lasers out anytime soon. 😊
 
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