difference between azolla and spirulina

[giridharan]

Dear sir, I have a basic doubt. What is the difference between 'spirulina' and 'azolla'.
is both for human consumption or for use in plants.How it is marketted? Is the climate in tamil nadu suitable for its cultivation?

 

[kanandiam]

how i cultivate spirulina

tamilnadu suitable place for cultivate spirulina which place suitable for cultivation