What do hydroponics do to weed?

Image by isnoop
The completed rig will have three long planters connected in parallel.

This early version includes the fan under the upside down container on the 5 gallon bucket lid. This will lead to an early failure of the fan motor, so I am working on a second generation design with a blower that uses an external drive.

Question by : What do hydroponics do to weed?
I’ve heard that hydroponics can add harmfull things to weed, is there anything you should look out for or be aware of?

What do you think? Answer below!