Hello, as you may have read in an earlier posting i am building a growbox. 4foot long x 2 feet wide x 4 feet high. I will be using a 250W hps lamp and an exhaust fan will be fitted. What i am unsure about is which grow system to use. I have read about Hydropod systems ( which seem expensive). I have also looked into a NFT growmat system. Cant i just fill a pot with pearlite or some other medium and stand it in shallow water? I would appreciate comments on best growsystems and mediums. Cheers Nick