Trying to understand pearling better

Dmaaaaax

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Jan 9, 2009
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Ok, so people look for pearling as a sign that their plants are getting adequete CO2. So my question is, does pearling happen based soley on the ppm of CO2 in the water or at a "perfect" ratio of CO2 to lights and nutrients in excess?

For instance if you get pearling in your tank then you add another 1wpg, does the pearling stop until you up the CO2 some more? Visa versa, if you don't have pearling in your tank just yet, but you turn off 1wpg, could you now get pearling because your lighting is now better in line with your CO2 output and nutrient demands?
 

ShaneSmith

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Jan 23, 2009
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'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
 

aquabillpers

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Jan 24, 2005
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Dmaaaaax;33129 said:
Ok, so people look for pearling as a sign that their plants are getting adequete CO2. So my question is, does pearling happen based soley on the ppm of CO2 in the water or at a "perfect" ratio of CO2 to lights and nutrients in excess?

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

Bill
 

VaughnH

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Jan 24, 2005
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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.