Pearling - What is its exact cause?

What causes Pearling - Please explain your decision in post

  • Increased CO2 Levels

    Votes: 3 20.0%
  • Increased Lighting

    Votes: 3 20.0%
  • Optimal Ferts

    Votes: 1 6.7%
  • Overworked Plants

    Votes: 0 0.0%
  • Saturated O2 Levels

    Votes: 8 53.3%
  • Other

    Votes: 5 33.3%

  • Total voters
    15

coach_z

AC Members
Jan 12, 2009
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Chris
So i changed up my co2 today to get rid of the glass diffuser and am running it straight into my powerhead. at the same time i was doing work on my tank and went from 2.16WPG to 4.33WPG (turn on my 2nd bulb to see) since then my drop checker went from green to yellow and my plants have been pearling....all of them, swords, sag, rotala, ludwigia etc.

What is the exact cause of pearling...

  • is it optimal co2 levels?
  • higher lighting?
  • combination of both?
TIA!
 
o2 saturation.
 
well, i found this on the barr report:
tom barr said:
No, not really.
It's just relative to the production of O2, or, the rate of plant growth.
O2 production = plant growth.
It has little to do with saturation.
Localized levels of O2 can hit 200%, while the water elsewhere in a weed mat will be 90%. Both locations can and do pearl.........

At high plant growth rates, obviously the levels will go over 100%, the higher the rate, the more pearling you see, but this has little to do with saturation, merely a correlation with growth, not really to do with 100% or more saturation at ambient.

Ambient saturation vs the maximum that can be dissolved are quite different concepts that do seem to get confused unless explicitly stated.

While much over 2-3ppm is considered beyond 100% saturation from ambient for CO2, we know we can add a lot more before you reach the point where you cannot dissolve more in the water. Likewise, for O2, however it's not nearly as soluble, but you can get a lot more than say 20ppm in there if you wanted to, it will degas, but if you add it faster than it degases, just like CO2, you can get more in there.

Regards,
Tom Barr
LINK
 
Pearling is when a plant is basically working near its maximum, its ripping the Carbon off of the CO2 molecule so fast, that your see a string of O2 molecules being released.
 
Anything beyond 100% is commonly referred to as 'supersaturation.'
 
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