I should rephrase that . I would like to know which Led and how many to use. I have a 40w x36d x 22h tank , the actual distance from the water lin to the sand bed is 20inchs. What would you recommend to cover the in say 36 x 30 area with enough par to keep every thing including clams on the sand bed. i am guessing 120 degree optics due to the depth of the water. but have no experence with these lights


