Just wanted to confirm my thoughts,

for plants to pearl a few things are needed.

optimal co2 30-40ppm
good supply of nutrients
2+wpg lights
good water flow.


So if all these are met why would plants still not pearl?

Too much water flow?

i would consider too much as leaves being blow over, this is not happening, they are moving around a bit but not blown over.

Well, just a thought as some mention that pearling can be limited if the flow is a bit strong.

I had 144 watts (36x4) PC fixture over my 72 gal tank (so pretty much right at 2 wpg) and had very limited to practically no pearling, I was dosing only Flourish micros at the time (likely decent nitrates and phosphates though from the fish load). Without changing anything else I replaced that light fixture with two Hagen T5 HO fixtures with 54 watt x 4 (though to be honest it seemed almost twice the brightness of the previous fixture to my eye, better reflectors and T5 vs. PC I guess) and within 20 minutes had VERY heavy pearling.

So maybe more light?

I have had plant leaves pearl when in the sunshine. The same species in the shade in the same tank didn't pearl.

This occured in a non-CO2 tank with 2WPG lighting.

A plant doesn't have to pearl to be healthy. Oxygen is a waste product from the plant's metabolism. It could be argued that a pearling plant is being overworked, it's metabolism being artificially raised and its life shortened as a result.

Bill

thanks for the info, how would you overwork a plant without having optimal conditions?

>>>>It could be argued that a pearling plant is being overworked, it's metabolism being artificially raised and its life shortened as a result.

Could very well be. But for most of us doing planted tanks that's the point!

I have 2wpg and I do see pearling, but only on about the top 3 or 4" below the surface. Light is a big factor.

Given optimal conditions, you can provide more nutrients or stimulation to a plant (or to most organisms) than it needs to live an "optimum" life.

Consider the man who lives in a perfect climate with clean air but consumes 2000 calories a day more than he needs. His body is being overworked and his lifespan is being shortened.

HTH

Bill

Not all plants pearl under the same conditions. HC, for example pearls profusely. But, my Limnophila aromatica, growing rapidly and very healthy hardly ever pearled. Pearling is enjoyable to see, because it is like a gold star on your homework, but it isn't essential for your plants to be doing well.