why is a white res more expensive than a black res?

i went to the store today cause i need more reservoirs and the lady at the store told me that the black res cost 100 ea (75gallon) and the white one cost 150 (also 70 gallon). the only benefit i could think of was that it was easier to clean but maybe it is made of better plastic? anyway i don't know why, does anybody else have an idea? or know why?

I think the white rez and trays are alot thicker than the black ones.

The white trays are made from virgin plastic which cost more to produce . The black trays can be made from 50% reground plastic and can be produced cheaper. The process used to make these trays is THERMOFORMING.

thanks a lot you guys. im definitely getting the white ones.

You could go either way.
I use a white 2x4 tray by Botanicare. It was affordable at the time.
I have seen very sucessful grows from Black Cement Mixing Tubs from Home Depot.

White coloring has to be man made so it cost more.

and awesome idea with the cement mixing tray, weeeeeeeeeeee I think those will work great for my idea.