Algae Bloom

[rosebudshoes]

I have a 30 gallon freshwater tank which, yesterday held 5 x albino cory, 6 x male Guppies, 1 x male Dwarf gourami, 2 x female dwarf gourami and 5 x Amano shrimps. Yesterday evening I added 2 more albino cories and 2 more amano shrimps. This morning I pruned my Cabomba plant and replanted the trimmings. I have quite a few plants on the tank along with driftwood. I have returned this afternoon to find the tank turning a white cloudy colour. I've turned off the lights as past experience has shown me that this helps but I'm wondering why it happened this time. My tank has been set up now for approx 3 months.
Hope someone can help??