Some one claimed, this is speculation, a huge pile of it...........that the grain sizes for the pumice is larger for larger tanks that are deeper, because of the increased water pressure, so they have large diameters to allows better diffusion to prevent anaerobic conditions.
This is a crock.
I can sell you diet pills, new age crystals too.
What is Powersand?
Pumice, and peat mostly, soaked in a terrestrial type fertilize(high NO3, low NH4) and some osmocoat like stuff added.
You can see 3 of these, and test the 4th with a simple test kit and some water.
When you up root the tank plants, the powersand mixes with the opposite colored Aqua soil. Folks tell people that "you must have the powersand", it's the key etc etc.
This is also a crock.
ADA aqua soil is great and contains plenty of nutrients for the long and short term.
Then there's no added cost nor mixing, nor layering monkey business.
ADA has some 100+ products, not all of them are critical to keeping a nice tank.
Why some assume it is, is not rational.
You go down and test one by one, what does what.
Then you know rather than use belief systems for advice.
Can I interested you in some Hydrilla Diet pills for 30$ for a months supply?
They are organic after all