A couple questions about my new flood and drain system

I just picked up a flood and drain system, basically for free. I have a couple questions that I originally posted in the Newbie Forum here:

Please help me figure out what I just bought!!!

However, I get the feeling that the few people who know what's up over there are too busy helping people with growing problems to help me figure out my equipment, so I'm coming to you guys since I figure most of you probably have the answers to my questions.

The pictures and explanation are in the link, basically I'm just wondering if I need to clean these tubs, if so how I should clean them, and how I can test the system easily before I put it in a box and set it aside for a while (my first grow will be in soil). Any help is very much appreciated.

Those balls are hydroton or expanded clay,which is a popular medium used in hydroponics.The bottom tray is the water/nutrient reservoir.There should be a pump in there if the system is complete.There should be 2 holes 1 that hooks up to the pump that fills the top tray and the other is the overflow pipe so when the water reaches the top of the pipe it drains back down.You can clean with 10% bleach and 90% water mix or hydrogen peroxide be sure to let dry for a while if you use bleach/water mix so all chemical residue evaporates.Same with the hydroton,and make sure you clean all the root matter out the hydroton.