Well, that thread sure makes a good read.👍
And I’m going to apologise in advance for this following long post. Brain is still ticking!!
Firstly I’d have to say that some of my perceptions have been somewhat altered throughout this thread and the additional related research.
I figured that light was THE driver and the mechanism by which you ‘manage’ your tank as such, with ferts/Co2 needed to match it and whilst this is not entirely wrong it’s not entirely right either. Geoff shows in his thread that growth can be controlled through ferts application when both light and Co2 is delivered in abundance (in line with
@JoshP12 thoughts) but it’s not simple. He has leaned out some, increased others, gone through periods of full EI (and seen a massive surge in growth) all without algae plagues, but this takes experience, quick response, and a really good understanding of how plants will react to specific dosing regimes.
Even with this knowledge, it’s still a pretty high maintenance tank and his attention to tank hygiene/waste removal was also meticulous.
Do-able yes, but not for the faint hearted.
The above with permanent full EI, would be an interesting ride for sure.
Words of wisdom given by many - if you have algae, or to prevent algae, lower your light. IMO, These are still wise words. Light may not be the problem per se, but slowing everything down gives you more room to get things wrong and/or allows you to fix the issue/deficiency before your tank crashes….and it’s easy. So long as you still have enough light, your tank won’t go into a sudden melt down. High light…..and your time to tinker is perhaps more limited. (Chances are either way, the actual issue is Co2 😂)
High light is also a bit of a misnomer. Not sure that we are really talking high light versus low light but rather highish light versus higher light. I’m guessing most Co2 injected tanks aren’t super low just maybe not full photon level.
The ramp up time issue, if I got it right, still requires you to reach equilibrium but with more than one way to skin a cat. The ‘normal’ method works….the rapid injection method works (IMO) as long as uptake and off gassing are high enough to control maximum ppm. (I’m still not convinced this gets you to 30mins ramp but hey ho) Higher light can increase uptake…I’ve got that….so the outstanding piece for me is off gassing really and specifically the mechanics of o2 and gaseous exchange.
So firstly;
Regarding rapid injection, I’m inclined to think that in most situations good distribution of 30ppm is going to cover your bases so, whilst I don’t dispute that a quicker Co2 top up may be slightly more optimal, I should imagine that the margin of difference in plant response/health is minimal. (I could be wrong) Maybe more so in a higher light tank but if you’re that close to the knife edge…..well I think I covered that! 😊
The rapid injection (including rapid off gassing) method, however, if applied well and ensuring equilibrium at 30ppm, still has the benefit of primarily only having Co2 in the tank when Co2 is needed or at least minimising Co2 outside of those times and for the fish, that is a good thing yes? My tank never fully off gasses, so not only are fish exposed to increasing Co2 for 3.5 hrs before lights on but PH only drops by 0.5 between Co2 periods. Surely condensing the time that Co2 is present, if it can be done safely, could be of benefit?
@arcturus mentioned, however, that higher surface agitation (which is the only way I would have of increasing off gassing) can reduce o2 saturation by off gassing o2 as well as Co2 and this is not a good thing.
So….Let’s assume that full o2 saturation is achieved during photo period via gaseous exchange and plant ‘respiration’. (High light may speed this but just good light should still achieve it)
Co2 is still at target 30ppm as equilibrium has been balanced at this point so Co2 level is fish safe (but good o2 levels still need to be maintained)
If we increase surface agitation, is the level of o2 that is driven off during photoperiod greater than the level of o2 that is gained via increased water surface?
I ask because, at night, when water may be o2 deficient (or in a tank with poor o2 saturation) increased water movement is advised to increase o2 levels.
Is it therefore the case that when water is o2 deficient it’s uptake of o2 from atmosphere is higher because effectively there is space for it. (Seriously dumbing this down I know but, in layman’s terms is that about right?) so night time agitation is good when o2 levels are lower (due to lack of plant produced o2) whereas during photoperiod, when the water may be fully saturated, the off gassing of o2 can be greater than the uptake of o2 and this can therefore create a net deficit?
If this is the case, if agitation is increased 24/7, would the disadvantage of o2 loss during photoperiod, outweigh the advantage of increased Co2 off gassing outside of photoperiod.
Thoughts?