I ordered mine at conrad. They got loads of different boxes. Mine is polycarbonate and has a moisture seal between the lid and box itself... As I'm going to install it in my greenhouse.
Oh, and i've got an update for the sketch...
Rewritten the pH algorithm. Which included incorporated 'smoothing' and a pulsing (on/off) effect for the dosing pumps.
Greetings... 
Hydroponic_Controller_v1_1_0.ino (45.7 KB)