Can you check this?

Hi everybody, this is my first post in this site but I have been reading your posts for a while and I have read a lot here, and I have taken some decision based on comments in this site. So I want to thank you all.
Now I have a problem and I want to get some opinion from the expeienced members here. My babies are showing green algaes in the rockwool cubes, so in another member´s thread I have read that it is very wise to cover the rockwool to kill algaes, and a simple recommendation was to use black plastic (like regular black plastic bag).
My question is, should I cover the black plastic as I have realized it reflects a small amount of light, and it probably creates a hot spot or just leave it on top of the "hydroton" as the reflection of the plastic is minimum. Please, check my pictures the first one without covering the black plastic, in the second picture I have covered it with expanded clay pellets. Which one do you think I should use?

I would take cardboard cutouts and lay it over the top not foil... paint the cardboard or w.e with white paint..

Take the foil off all together, let the rockwool breathe. The algae is from the fact that the airflow is not sufficient and the water is sitting still in the rockwool.
As for it taking ur babies food, i dont think they require nutrients just yet anyway, they are still rather young.

Thank you all.
GG13, I agree with you, I was really thinking that this foil could NOT be a good idea. Some other member said he/she used panda foil and algaes disappeared.
XxNinjaxX, you are right some water is sitting still in the rockwool cubes, probably too wet and this brought me the algaes problem, and yes I am giving them 1/2 strength nutes, as they are already 15 days old and my medium is expanded clay pellets, which has not nutes at all. I think Doobiee´s recommendation with cardboard is easy, and it will not allow the algaes to get any light

Here I am again, my plants are doing great! I have waited a little like XxNinjaxX has suggested and a couple of days ago I have covered them with expanded clay pellets (my midium) as I was adviced in another site.
So I have built the net (I am doing Scrog), but I have 5 spaces under the net, my set up have 24 pots, but I have only 19 plants, now my question is, should I leave those 5 spaces in the middle, where more light is, and work the plants bellow the net from the outside to the inside, as they will be looking for the light, or viceversa. I think it is better to work the plants to the lights and not against the light, but sometimes logic is nothing and experiences is all that counts
So experienced members, can you help me?
Please, check the pictures