Is there not a certain height I have to go to get spread from front to back 50cm?I use Fluval lighting and rest the lights directly on the rim of the tank, and still have difficulty with high-light plants, so I would say "as close as you can get it without permanently submerging it", unless you're happy with low-light plants.
I bought a floating shelf from Argos (£12) and used the spare brace bar that comes with the DD - Jump guard. Cut and drilled a couple of lengths of the bar and screw them to the underside of the shelf with 8cm extending out, the light sits neatly on itWhat have you used for mounting it? Looks very neat. I have mine on the tank rim, but I think it needs to come up a bit as I tend to get algae growing around the floating plant roots but not further down in the tank.
Thanks for the advise, I’m going to leave it as is for the time being as I’m pretty happy with it but if it needs it I’ll lower it further.i lowered mine down until there was no light spill on the wall.
if you can get it down that far then light hitting the internal glass will mostly reflect back into the tank. At this point you are wasting about 25% of your light onto the wall and into the room.
https://store.marinebeam.com/beam-angle-calculator-1/Is there not a certain height I have to go to get spread from front to back 50cm?
So for a single row and if you want a "spot size" of 50cm....14.43cm from the diode lens face to the water line us where you would start.
Assume the diodes have a beam angle if about 120 degrees.
For multiple rows just use the radius for front to
back and add the front diode to back diode distance.
Say 6cm fron center of front diode to center of back diode.
So 50-6 =44 /2 = 22cm radius.
So tangent of 1/2 the beam angle =1.73
@13 cm height is approx 22cm radius.
Obviously the higher up the less par at the substrate.
All depends on your goals and wants/ needs.
Keep in mind generally the "spot" is very unequal in light falloff w/ the majority un a small central region and "other things" as explained in my link.
FWHM concept of the beam
So in effect you can go lower than calculated and still gave some light in the entire 50cm at the surface. It will just be low.
Really you only need a starting point and adjust to taste.
For any tank over 40cm deep 2 lights are ususually beneficial unless shallow, say 35cm or less
In your case say 12+40-5 =47cm will be your farthest and weakest light point.
Par has reporteds to be about 63 w a 3" offset and at 19" depth (48cm) with all channels at 100%
Hi.I use Fluval lighting and rest the lights directly on the rim of the tank, and still have difficulty with high-light plants, so I would say "as close as you can get it without permanently submerging it", unless you're happy with low-light plants.
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