light meter lux

first post! - Hi all I'm the idiot and this is the meter: Pocket Light Meter - CEM DT-1300 the scale reads up to 2000 which i assume = 50,000 lux when the biggest scale is selected. So to get 30,000 lux (minimum for good growth) I need a reading that is 3/5 of 2000 = 1200 ? can someone...