Something you should
really consider doing is building a large spill tray for your system. With hydroponics, you
will end up with water on the floor. Its almost inevitable. Imagine if you took a 5 gallon bucket of water, and just poured the whole thing right there on the floor. Even with as little as 5 gallons, very significant damage can be caused, undoubtedly costing money and time. Now, think about the massive amount of water on the floor if all the water in your system ends up on the floor.
Building a big spill tray is very easy, and is less than $100. It will save you so much heartache, believe me! Just build a frame with some wood, and get a pond liner (available everywhere) to hold the water. Dont use poly plastic sheeting, its not durable enough IMO.
Take a look at my grow thread link below in the signature box. I usually have around 60 gallons in my RDWC, and my tray holds about 100 gallons. I could dump all the water in my system, with lots of room to spare.