There is no need to run CO2 at night, plants will not use it when lights are off. Tried it, no effect. Plants and fish regulate their internal pH any way so no use in keeping it stable, how stable is stable ? Not all nutrients benefit from low pH.
If you really want to keep your CO2 stable, remove all potential acid/alkaline leaching sources and get a PH controller. It may not stop the pH from going below the set point but it will stop CO2 injection when the pH drops below that. If you do not have a massive acid source or CO2 bubble this will stop the pH from going down pretty soon.
Without a pH controller you have to get extreme degassing and very high CO2 input for a stable pH. Degas enough so that plant use during the day is very small compared to your degassed amount, add enough CO2 so you get 30ppm despite the extreme degassing.
Using any of the above you will you your tank about 3x as fast. Add to this that large tank have great inertia and will not fully degas by the next day anyway. So if the drop from atmospheric equilibrium(so called "degassed") pH is 1 at lights off, you will likely get a 0.5 increase by the next day with decent aeration. So overall you have a 0.5 daily swing and no plant benefit. Worth the 3x consumption ?
I would not do it for the reasons given in the article. Fish and plants experience pH change all the time in their habitat. Lakes behave like our aquariums and get even more stratified. River water will vary greatly depending on how much rain is received upstream.
Also, many of the things in the article were debunked about 15 years ago in the hobby or just wrong. Interesting to see that AGA is proud of such an article. Speaks volumes. So I question the premise of the change. Some examples of what I am speaking about
In the absence of CO2, many plants have the ability to meet their carbon needs by splitting carbon
directly from carbonates in the water, which is the second method.
Actually it is a minority of the current plants in the hobby, mostly those obligate aquatic plants.
The amount of CO2 needed in the aquarium for good plant growth is considered to be around 15 milligrams per liter (mg/L),
Most sources and plant growers go for 30 and above , but glad to see her using the correct units mg/L not ppm.
Room air contains 1 to 3 mg/L of CO2, and aerated water dissolves only 0.7 the CO2 content of the air.
Thankfully for all terrestrial plants, air contains somewhere between 350-407mg/L, just 100x more nothing major.
In fact, the proper use of supplemental CO2 with appropriate lighting and trace element supplementation should actually increase the levels of dissolved oxygen in the water.
We have CO2, light and trace elements. Where are the macro nutrients ? Pretty sure the O2 levels will not increase without them. Oh wait here they are:
If the two major nutrients in the tank (nitrogen products and phosphate) are increased beyond the needs of the plants, you will experience algae problems.
Man, see told you non-limiting nutrients are a lie. Tom Barr's aquariums are full of algae with all that PO4 sitting there in water.
However, if the water is not properly buffered, or if too much CO2 is introduced, the pH in the tank can drop quickly to levels that are lethal to fish.
Oh, pH levels and fish... Pretty sure it is the CO2 that kills them at that point. In normal aquariums, even with low KH you will not need to go lower than pH 5 with CO2 injection. If you do, you added to many other acids to the tank. Plenty of counter examples here as well of people with low KH, CO2 injection and good plant growth.
Those aquarists with very soft water must increase the alkalinity of their water. Without the buffering properties of KH, CO2 supplementation can cause the pH to plummet, to the detriment of plants and, more especially, the fish.
Now it seems it is a must, it does not matter that in the aquarium are some fish and shrimps which need low KH. And plants seem to also be affected by low pH. Let's see... no Vallisneria
still grows at a pH below 6, Egeria
as well... other high pH plants in mind ?
The goal should be to find a rate of CO2 supplementation that falls within this range, and produces a pH reading that is neutral (7.0) or slightly below
So if the water already has a pH of 7 or slightly below, the CO2 goal was achieved ??? Or if it is above 7 but fish are gasping ?
Think a better goal would be to add enough CO2 to cover the requirements of your plants under the supplied amount of light. If this is too much to keep fish alive, reduce the light intensity.