Hello i just bought this lights from eBay and Iām leaving them on for 12 hours in total. Would turning the blue lights on for like 1 or 2 more hours affect my plants at all or I shouldnāt worry?
That light is high in the blue particularly, and this can promote algae. I would reduce the 12 hours down to 8 and monitor. As for the blue, yes these can affect plants and more importantly fish. Used as a "dawn/dusk" period this might be OK, but keep it minimal.
My lights have a blue / moonlight setting. As @Byron suggests I have these on half an hour before and after the main lights for dawn / dusk, but they are turned off most of the time the white lights are on.