Fill with water and cure for 30 days. keep moist when set, then I added water about 4 to 6 hours after constucting. Materials 1.5 bags cement, wire, 9 buckets sand, rerod, and tie wire. Affnan type drain tube with a flange glued on set halfway thick in cement bottom. Two guys 3 to 4 tanks per week. Maybe more if you figure it out, maybe less when you get tired of making these.