A question from the hydro tutorial:
Why is it important to wash the expanded clay balls before using them?

Is it advisable to clean the water containers after x amount of time? Perhaps there could be a deposit build up or something that the plants don't like.

I was going to grow a rocoto as a long term 'family' plant (for many years). I hear they are more like woody shrubs though. So, would a passive hydro pot like  this be a bad idea? I'm guessing if the roots get big and woody, it will mess with that divider space between the pot and the water.
(http://i.imgur.com/7MpUr.jpg)

You'll need to rinse clay pebbles properly to stabilize ph-balance and get rid of that dust. After doing that, there is no need to wash containers afterwards.

The roots will be big, but you should put some gauze into pot before clay pebbles and plant.
That prevent the roots growing into water container.

Hopefully that helped out...