Green Water Cultivation

Okey i started with taking&putting used dirty water (from the water change) to a spare tank. this is dirty water, kind of brownish in color. put in air stone 24 hours a day under open sky (yet limited period expose to direct sunshine)

for the passed 7 days it turn from brown to yellowish then a bit (light) greenish now. i hope later it will get greener.

so what then? can i put the babies to this green water(originally dirty) ? it smell like the soil now. if yes,
how long can they stay in there?
when do i change water?
what do i do during water change so it back/stay green?

i'm confused!!!??? hope you guys can help.

Another problem: now i got tiny worms moving at bottom of the tank. Ayyoyyo..what to do?

thanks,