thinking about working my rock work and sand so the refugium light will glow the bottom if my rock work like under water lava kinda like a what yould see in big island kinda..... Any toughts????
What the heck. Do it. You can always turn them off if you don't like it.
Excess nutrients will always be the cause of algae. Light spectrum is a limiting factor.
Common float glass tanks do not require support in the center. Just the bottom rim.
If you have hallow areas under rocks or a stack like a volcano you could get submersible LEDs. I'd use 12 volt dc marine lights commonly attached to the stern of a boat. You can find them pretty cheap on eBay.
I know they're sealed, but most have the wire run through the bottom and some portion sticks in thru a hole in the transom. Course, I haven't looked at the flat mount ones because I want a clean look on my transom.
it doesn't matter how many nutrients there are if there isn't enough light to grow them. nutrients, flow and light are all equal in the cause and treatment of most algaes.