The sooner towards the lights coming on, the more the plants can use it. Plants only use carbon and ferts during lighting periods, so putting it in 2 hours before the lights go off is sort of pointless. It's like putting out a 4 course meal at 1am when everyone is just going to bed. It's just going to sit on the table and rot all night.
20g platy, , 2 x 10g shrimp, 3 x 20g shrimp, 7.5g shrimp and 1 great dane/mastiff puppy.
Sump Pimp #2
My Tanks and my shrimps