How to Setup top DIY top drip bucket for SCROG?

I see the airstones the water pumps the bucket with the net pots at the top. I have watched youtube videos on it but still cant grasp the concept. How is it top drip is supposed to work and how do you change the solution when doing a SCROG which can't really be moved upward to change the water?

there are a few ways to do this, one way is to build up your own screen that is attached to every single bucket that way when you lift the lid the pot, screen and everything is attached as one piece, the other way is to build a platform for all the pots, screens attach to use some sort of ratchet pulley system so the whole platform lifts as one piece and all that is left behind is the buckets (this is what i did see pics), also you could use a control res that is attached to all the buckets with some tubing so all you would have to do is throw a pump in the control bucket and it would drain all the others, then just fill them again.

As drgreentm pointed out there are many ways to accomplish this but his setup IMO is ideal. The only thing that could make it better would be being able to access the back for training.

greentms is really nice. You can also drill a bulkhead and ball valve into the bottom to drain it.