Lighting Question

goody · Mar 4, 2023

I'm really loving my macroalgae tank I recently setup and am now considering building a "real" macro display tank.

I wanted to get a full spectrum light for the tank instead of using what I had lying around the garage, so I did a little bit of research and kept it on the cheaper side and bought a hygger 999 auto on/off freshwater light knowing I would have a good spectrum and watts/gallon. I did find a chart showing PAR readings at 3 different depths which is my question.

How much PAR do the macros need and what is too much? Or maybe I should ask how would I know if they are not getting enough or too much PAR?

The brackets on this light have it sitting right on top of my tank and I'm currently running it at 90%.

Slocke · Mar 5, 2023

goody said:
I'm really loving my macroalgae tank I recently setup and am now considering building a "real" macro display tank.

I wanted to get a full spectrum light for the tank instead of using what I had lying around the garage, so I did a little bit of research and kept it on the cheaper side and bought a hygger 999 auto on/off freshwater light knowing I would have a good spectrum and watts/gallon. I did find a chart showing PAR readings at 3 different depths which is my question.

How much PAR do the macros need and what is too much? Or maybe I should ask how would I know if they are not getting enough or too much PAR?

The brackets on this light have it sitting right on top of my tank and I'm currently running it at 90%.

Depends what macros. Some like caulerpa love a ton of light but others like dragons breath prefer less.

goody · Mar 5, 2023

Slocke said:
Depends what macros. Some like caulerpa love a ton of light but others like dragons breath prefer less.

Thanks for the reply. I have jumped into this macro tank and already have 12 different macros. I can always put those that prefer less on the outer edges of the tank because the fixture I bought leaves 3" on each side not directly under the light. The PAR test that was run on this light had these numbers:
408 @ .5" below surface
140 @ 11" below surface
103 @ 19" below surface.