I got the new light, last Friday, also i have 4 clamps, two on rocks, two on sand, they do just fine, i move it Sunday. One is 7 1/2" big (i have this for 5 years). I down size from MH 2x 150 W-4 T5 54 W. 150 Gal. to 75 Gal. LED, Thank's to my boss, i use to have my tank at work.