Radion Diffuser - Lower lights?

[Mirkus]

My radion diffusers arrived today. How far do I have to lower the lights to maintain the same par?

 

[Reefing Madness]

@Dana Riddle

 

[Dana Riddle]

Ecotech Marine says the overall light loss is 20% when the diffuser is installed. So there are a couple of options - lower the luminaire a couple of inches or slightly increase the output. But here's the tricky part - if your PPFD (PAR) level is over about 400, loss of 20% isn't going to make much of a difference since the coral's zooxanthellate are probably at photosaturation (that is, a maximum rate of photosynthesis.) If your PAR is at 100 at the bottom and 300-400 at the top, you'll be in pretty good shape *in most cases.* It's OK to provide more light if you're looking for corals that are fully colored (such as the pinks and blue chromoproteins seen in some corals), but it has been my experience that there is a trade-off - fully saturated color is often associated with slower growth. If you can share some PAR or lux numbers we can get a better idea of what's actually going on.

 

[Mirkus]

Thanks for the reply. I was trying to lower my lights without the benefit of a Par meter. I was running at 70% intensity 14 inches AWL. I took a shot in the dark and lowered my lights by 3 inches. Everything looks fine, except for one coral. It went from dark brown with a hint of color to light brown.

 

[Dana Riddle]

Thanks for the reply. I was trying to lower my lights without the benefit of a Par meter. I was running at 70% intensity 14 inches AWL. I took a shot in the dark and lowered my lights by 3 inches. Everything looks fine, except for one coral. It went from dark brown with a hint of color to light brown.

If the dark brown to light brown shift occurred within a short time frame (less than a week or so), it could be due to too much light.