Lifetime Charter Member
Lifetime Member
Mar 14, 2007
SO light, co2 and nutrient drive growth?,( if light, co2 and 02 drive pearling?) I have a new understanding of par and light penitration so i've reduced my lighting by 1/2 and still have a high light tank. before doing so, my tank would begin pearling 1 and 1/2 hours after lights on. since lowering the light i've noticed a huge drop in the pearling. so i've increased the amount of co2. now pearling begins about 3 hours after lights on and is nowhere as profound or beautiful as it was. given that not much has changed except 1/2 the light.what am i missing out on? Why is the pearling so whimpy? ( or is this just one of those things that will reach equilibrium, and patients is in order)
thanks in advance tom. Guy from albany aquarium says hi.


Guru Class Expert
May 23, 2009
I found the pearling came slower too. But now it seems my plants have adjusted themselves.
Try waiting for about 2 weeks. Anyway, the amount of pearling is not as high as before.
Seems OK to me, they are not dying, just grow slower.


Lifetime Charter Member
Lifetime Member
Mar 12, 2009
Metabolism drives pearling from O2 being put off at the leaf faster than it can be removed, light drives metabolism.

Tom Barr

Staff member
Jan 23, 2005
Less light=. less growth as it should be, so less O2 production and less observations of O2 pearling.

As you increase the rates of growth, you increase the rates of pearling all other things being equal.
As mentioned, plants do take a few weeks to adjust to lower light, they produce more Chlorophyll to catch more light. This requires reworking of the light catching complexes, and changes in the accessory pigments that catch other wavelengths.
If you have higher light, then the plant gets "fat and lazy", does not need as much Chl and pigments to catch the same amount of light.

So it will divert resources elesewhere. Same deal for CO2.

So low light+ high CO2 is a the best combo for controlled growth, easy adjustment of CO2/nutrients, and still nice looking plants.

The trade off is that you have slower growth and less pearling, but you still have pearling none the less.
For pruning, management, this is often what folks want. Trimming stem plants weekly might be okay for awhile............but after a few years, most get tired of it.

Tom Barr