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Re: [APD] Pearling after water changes, some experimental observations vol 1

Thomas Barr wrote:
> Why would the plants not have bubbles after the water change,
> then formation occurs 15-30 minutes later?
> The water is at equilibrium so no degassing is going to occur.
> The only reason I can figure out to such a degree that
> influences plant growth like this is due to exposure to air for
> 5 minutes.

It could be the result of myriad variables working alone or in concert.

> What is in air that's not at high levels in the tank that would
> induce intense growth?
> CO2 in the gas phase.

What causes you to assume that the causation is due to exposure to any 
particular substance in the atmosphere? Without further information it 
is equally plausible that the stress of being exposed to air temporarily 
increases the metabolic rate of the plants.

> This shows/strongly suggest that aquatic plants can dramatically
> increase production and growth if they are supplied with a gas
> phase of CO2.

There is no evidence of that yet.

> It's a simple test and the observation #1 shows that it's not
> due to degassing tap water etc, it's due to the gas phase
> exposure to air.

Exposure to air may cause pearling, or it may be a rapid temperature 
change, or five minutes without dissolved nutrients, or any number of 
possibilities not yet controlled for.

> So I tested the before and after O2 levels at the same time I
> did the water change above. I had 7 ppm(100% a tad over) before
> and 11ppm after(t= 2 hours) or about 160%.

You succeed in demonstrating that the plants aren't pearling out some 
other gas like helium, and that the production of that gas is increased 
after the water change. This doesn't get us any closer to the cause of 
that increase.

> As far as I know, this is the first demostration without a O2
> meter to show and confirm that pearling in this case was due to
> gas phase exposure to CO2. The backup with the O2 meter offers
> more support for the contention as well.

That plants pearl after a water change doesn't confirm that exposure to 
gaseous CO2 is the cause. It only confirms that plants pearl after a 
water change. There are hundreds of variables present that aren't being 
controlled for.

"He who throws dirt is sure to lose ground."

Jerry Baker
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