Light intensity question

[G&B Reefing]

Hi!

This question has been bouncing around my head for a while.

A bit of context before the actual question. I have a nano tank with a single point red sea led50 light. I have been trying a few sps varieties with very little success.

All them internets say sps should be at 200-300 par or higher. With a single point light i have to up the intensity to 80%+. I have recently added an ai blade to complement and help with shadowing. To achieve the same par range i had to back off the led50 to ~60% (with the ai blade at 40%).

This got me thinking… although my total par in that area is equivalent between the two set ups the surfaces of the coral do not experience the same intensity. For all you engineers out there this would be similar to calculating view factors for thermal radiation effects on a solid body…. Basically this is line of sight intensity calculations….

So to my question. When we talk about sps, is par the end all be all or should source intensity also be in the discussion? Also, does the concept of shadow reduction on sps effectively result in this lower intensities that make sps coral successful?

Thanks!

 

[MoshJosh]

Not an engineer, but as a function of practicality I think PAR is a good measure (when it comes to lighting of course and assuming you have proper spectral coverage). . . Are there like a billion other factors when it comes to lighting? Sure. But unless you have already reached a plateau of SPS growth I would not start worrying about them personally.

 

[areefer01]

Hi!

This question has been bouncing around my head for a while.

A bit of context before the actual question. I have a nano tank with a single point red sea led50 light. I have been trying a few sps varieties with very little success.

All them internets say sps should be at 200-300 par or higher. With a single point light i have to up the intensity to 80%+. I have recently added an ai blade to complement and help with shadowing. To achieve the same par range i had to back off the led50 to ~60% (with the ai blade at 40%).

This got me thinking… although my total par in that area is equivalent between the two set ups the surfaces of the coral do not experience the same intensity. For all you engineers out there this would be similar to calculating view factors for thermal radiation effects on a solid body…. Basically this is line of sight intensity calculations….

So to my question. When we talk about sps, is par the end all be all or should source intensity also be in the discussion? Also, does the concept of shadow reduction on sps effectively result in this lower intensities that make sps coral successful?

Thanks!

Welcome to the great debate. Hobbyist have different opinions on it. Myself included. I will just say if you want to learn a bit about lighting, intensity, if there is a thing as too much, and more do a quick search for Dana Riddle. He has done real world studies, oceanic, on light and the effects it has on some corals. Note that the coral tests are of course limited but the data is still applicable to our home aquariums. He also has at least one MACNA presentation that I recall if not more.

Well worth your time.