Trying to understand pearling better

'Pearling' is when the plants are releasing enough O2 that it no longer is able to dissolve in the water... the water is O2 saturated. This occurs when the water does not have a O2 sink (Organisms bacteria fish etc..) (Think of it as a drain), and the photosynthetic rates are high. The goal of Co2 addition is to increase PS rates.. that is why people use it as a guage. For a high PS you also need there to be no limitation factor in photosynthesis. So it is not so much a ratio as not limiting anything that would cause plant to reduce PS. Hope that helps

 

I have observed "pearling" in a non-CO2 tank, on plants in bright sunlight. Nearby plants not in sunlight did not pearl.

Bill

 

Pearling is a result of fast plant growth. Once you get above some lower light intensity the plants will be driven to grow fast. If you don't have adequate nutrients, including CO2, the plants can't grow fast, so little pearling, if any. If you now add CO2, but not adequate fertilizers, the plants still can't grow fast, so little or no pearling. And, much more typically, if you have non-limiting fertilizer concentrations, but inadequate CO2, you get little or no pearling. At this point, increasing the bubble rate on the CO2 can get an adequate amount of CO2 available to the plants and you get pearling. That is why when increasing the bubble rate, watching for pearling as a sign that you now have enough is a good idea.