I am also trying to understand this. By what you said above, does that mean:
1. we monitor our drop checker the 1 hr when lights are on, make sure drop checker stays (lime green). This is because the first few hour when lights are on, things starts to become unsteady, and our goal is to make sure things are steady throughout the photoperiod. and therefore, we have to make sure during the last 10 min during lights on that drop checker is still lime green.
2. when Rev turns on his co2 24 7 he may not have achieve steady steady state from the go of his photoperiod and this leads to fluctuation in co2 level.
Thanks for your input.
The goal is not the last ten minutes. It is indeed the whole photoperiod! Surface agitation was once recommended to me by plantbrain, aka Tom Barr. I now see the multitude of benefits by having it, it provides a steady gas exchange of c02 and oxygen. By exchanging c02 u are preventing a buildup of c02 from happening this is how consistency is achieved. Most pressure regulators and needle valves we use are very precise for our needs so the problem does not lie there, but in the concentration of the water column.
What u are trying to achieve if I were to put into numbers. For example beforeu turnon c02 uhave 1 ppm of c02 in the water column. C02 on. When lights come on u are striving to reach say 20 ppm. U reach that. Keep it there all day. Lights grout. C02 off and u start the process over. Plants will prepare their metabolism for that amount of c02 and will produce enzymes accordingly.
U start the day with c02 on and reach 20ppm but Blythe end of the day dur at 38ppm with a yellow drop checker, fish seem fine and plants are pearling. Ur happy! The problem is, tomorrow morning, ur plants want 38ppm not 20. And trust me 38ppm is not a lot, I've been much higher and 30 seems to be a common zone on here but it's a figurative number. Oxygen levels will determine much off how much c02 can be added. Plants and light determine how much u need. They will owever adjust to how much they are given to a certain extent much the same as an animal will adapt to available food and water supplies.
I do not measure c02 by drop checkers anymore. I've used digital equipment, and tritation kits and drop checkers at this point just let me know my c02 is still working. I base my levels off plant growth and fish respirations per minute.
I don't want to over inject any tank, it's wasteful. Not every tank will need a lime green drop checker as reference. Some may need yellow some may need just turning from blue to green. It all depends on the plants and the amount of c02 they require for the given amont of light.
As for 24h. It usually reaches an equilibrium at some point and will go no higher. In most cases when running 24 hours the issue will become not enough c02 for the amount of light. Airstones, can be beneficial or detrimental here. They burn off c02 fast. Some run them at night to keep c02 from building up. The key there timing as to when it comes on and when it goes off. The beneficial part s added oxygen which definitely helps prevent algae and does help the bio filter as well.