Help! Best way to grow Biofilm and algae?

[wandaywang]

Hello
Been looking on line for ways to grow algae and biofilm to feed my shrimp and other grazers - - butterfly loach and goby (stiphodon ornatus)

So far what I've seen are people just putting rocks in an outdoor water container and wait for the algae to grow. or for biofilm glassware in a vase next to a window sill.

What is the most efficient way?
How long does it take for a decent amount to grow in?
What about mosquitos breeding in that future algae garden?

Thanks for your help!