Great Gillguy, thanks. Did you agree with the 90 angle on the lenses?
If the lights will be under 10 inches from water line yes and 120 on red and green. If above 10 inches then you can use 60 optics for better penetration since your tank is 24 tall.
I will be mounting my S-120 @ 12" above the water line and Kevin has suggested to use all 120 optics. Not real sure on this, tank is 24x24 square. I was thinking 90 on all but the red, green and UV. I only have 1 each of the red and green and 2 of the UV, thinking of increasing the UV count to 4 total, just not sure.
Too many options