Request for Information

[Larry_In_Missouri]

I have been a marine hobbyist for decades. Have transitioned through VHO, MH, T5, and LED lighting. This week I received my Apogee 420 USB PAR meter. After familiarizing myself with it, I drew up a chart and (with my wife as secretary) took some measurements. One of my tanks (120g,2X2X4) has 8 T5 HO bulbs of mixed temps (actinic, actinic white, daylight, etc). The other I began with is an 80g (3X1,5X1.5), currently undergoing some revisions to make it dedicated to seahorses, pipefish, and like requirement species. As a temporary measure this tank is lighted with LED full spectrum grow lights (the cheap Chinese ones you see on the internet and on hydroponic sites. To my great surprise the LED's gave higher readings of PAR at virtually every depth and location (water depth: 6", 12", 18", and or bottom of tank). The LEDs were predictably more directional with intensity falling quickly outside the footprint of the fixture, but I can not comprehend why these relatively cheap fixtures should compare in any way, to my "flagship" setup of the array of T5 HO's. So, what am I missing?

 

[Flippers4pups]

I have been a marine hobbyist for decades. Have transitioned through VHO, MH, T5, and LED lighting. This week I received my Apogee 420 USB PAR meter. After familiarizing myself with it, I drew up a chart and (with my wife as secretary) took some measurements. One of my tanks (120g,2X2X4) has 8 T5 HO bulbs of mixed temps (actinic, actinic white, daylight, etc). The other I began with is an 80g (3X1,5X1.5), currently undergoing some revisions to make it dedicated to seahorses, pipefish, and like requirement species. As a temporary measure this tank is lighted with LED full spectrum grow lights (the cheap Chinese ones you see on the internet and on hydroponic sites. To my great surprise the LED's gave higher readings of PAR at virtually every depth and location (water depth: 6", 12", 18", and or bottom of tank). The LEDs were predictably more directional with intensity falling quickly outside the footprint of the fixture, but I can not comprehend why these relatively cheap fixtures should compare in any way, to my "flagship" setup of the array of T5 HO's. So, what am I missing?

Pulling the lenses off helps blending and shadowing. Less focused beams of light, though not completely. T5's will always be better for blending and light spread.

 

[KrisReef]

Not sure if I read this correctly, but a new (clean) tank with LED's had better readings than a running set-up with ("dirty") water that might be the source of light scattering?

Just a WAG.

Keep your hands off the secretary!