par meter test results

james30ct · 08/30/2014, 01:02 PM

So our local club has an apogee par meter that a borrowed to test my tank. I have a 155g bowfront with 3 reefbreeder value fixtures. tank is 24 inched deep.
I have the blues set at about 75% and the whites at about 65%

I am getting mid 300's at the top of the tank and 90-100 at the bottom. I have a squamosa on the bottom that does good and various sps throughout the tank.
Should I be concerned that the par is so low on the bottom? I know par is different with leds but not sure whats ideal. I also have a gig anemone on the bottom that also does ok.

Thanks for any input. I did the test with all powerheads off.

Nano sapiens · 08/30/2014, 02:40 PM

If your corals are doing fine, then you are providing enough PUR (Photosynthetically Usable Radiation). PAR is useful for determining intensity of all visible wavelengths (400-700nm), but corals don't use/need all of these wavelenghts since zooxanthellae photosynthesis is driven by violet, blue and red (only shallower water corals receive red in nature). LEDs tend to be heavy in the bluer wavelengths, so that's why corals under lower PAR can still receive adequate PUR.

08/30/2014, 01:02 PM	#1
james30ct Registered Member Join Date: Jan 2012 Location: Groton, Ct Posts: 1,218	par meter test results So our local club has an apogee par meter that a borrowed to test my tank. I have a 155g bowfront with 3 reefbreeder value fixtures. tank is 24 inched deep. I have the blues set at about 75% and the whites at about 65% I am getting mid 300's at the top of the tank and 90-100 at the bottom. I have a squamosa on the bottom that does good and various sps throughout the tank. Should I be concerned that the par is so low on the bottom? I know par is different with leds but not sure whats ideal. I also have a gig anemone on the bottom that also does ok. Thanks for any input. I did the test with all powerheads off. Last edited by james30ct; 08/30/2014 at 01:13 PM.

08/30/2014, 02:40 PM	#2
Nano sapiens Registered Member Join Date: Mar 2009 Location: East Bay, Northern California Posts: 658	If your corals are doing fine, then you are providing enough PUR (Photosynthetically Usable Radiation). PAR is useful for determining intensity of all visible wavelengths (400-700nm), but corals don't use/need all of these wavelenghts since zooxanthellae photosynthesis is driven by violet, blue and red (only shallower water corals receive red in nature). LEDs tend to be heavy in the bluer wavelengths, so that's why corals under lower PAR can still receive adequate PUR.