Can i use...this

Can i add a 4100k 200w to my current grow(42 days flower) or is it pointless since its 4100 and the plant will not use alot of the light correct?

better off getting a 150/200w 2700k

I have it just laying around i removed it when i went into flower.

I'd use it

yeah you can always use dual spectrum.

id suggest making sure you have more 2700k though