I've seen a lot of comments on this lately saying that pearling doesn't happen till the water column reaches O2 saturation. Has anyone actually tested dissolved oxygen levels relative to pearling? I'm betting not. And I have another hypothesis of what causes pearling that makes more sense (to me anyway.) Seems that this could be tested easily enough though. Dissolved oxygen tests aren't particularly expensive.
My theory is that pearling has nothing to do with the water column reaching O2 saturation. Instead, pearling is simply a product of a plant producing oxygen faster then it can dissolve in water. Unlike CO2 which is easily & quickly dissolved, O2 isn't taken up as quickly or easily. If I stick an air tube into a bucket of water & pump O2 through it you wouldn't suggest that the water column has reached saturation just because there are bubbles coming from the tube. Similarly, I can start & stop pearling in my aquarium just by controlling the light intensity. Within a couple minutes of doubling the light the plants start bubbling. Turn the light off & the bubbling stops in a couple minutes. It's reliable & repeatable.
Just thought I'd take a second to question some "common" wisdom on pearling.
My theory is that pearling has nothing to do with the water column reaching O2 saturation. Instead, pearling is simply a product of a plant producing oxygen faster then it can dissolve in water. Unlike CO2 which is easily & quickly dissolved, O2 isn't taken up as quickly or easily. If I stick an air tube into a bucket of water & pump O2 through it you wouldn't suggest that the water column has reached saturation just because there are bubbles coming from the tube. Similarly, I can start & stop pearling in my aquarium just by controlling the light intensity. Within a couple minutes of doubling the light the plants start bubbling. Turn the light off & the bubbling stops in a couple minutes. It's reliable & repeatable.
Just thought I'd take a second to question some "common" wisdom on pearling.