Pressure/ vacuum on preciptation of a borax saturated solution

Trying to go back to my collage chem/physics. We put a supersaturated solution of borax on the stove. (heated water, added borax till it would not take more borax). Placed them under vacuum 15 inhg, normal pressure, 20 psi. Initial hypothesis was crystals would grow better vacuum. They do this in space vacuum and low gravity. But we can't get rid of gravity. 


Results by weight of new jars with crystallization using the same size pipe cleaner for nucleation:


* pressure: 467.4g
* reg: 454.5g
* vacuum: 326.3g


Definitely more crystal deposition in higher pressure, less uniform
reg pressure most uniform deposition on pipe, less deposition
vacuum, least deposition


Did the air pressure cause the solubility to drop, resulting in more crystals?  

And the vacuum less crystals because of more solubility?


I initially thought it would be the opposite.


What's the explanation?  

Don't know if you would observe differences under a microscope for quality of crystals.


