Par on an actual Reef.

[Sdot]

Hey family, hope all is well during the pandemic. I was messing around with my Apogee 510 Par meter and decided to do some measurements outside in the air. It was reading near 2400 par! So i decided to fill a small bucket of water (around 10 inches deep) and collect readings underwater. The par quickly dropped from 2400 to around 1524 in just 10 inches of water, so im curious about high powered reef lighting and at what depth would the par levels in the ocean be similar to what we are getting in our home reefs.

Is it safe to say that corals are seeing similar par numbers in lets say 10-20 feet of water as they see in our aquariums at 25 inches? Anyone ever take par measurements during a diving trip...really curious.

 

[oreo54]

510 isn't accurate in air...............more correctly it's internally corrected for water:

The MQ-510 sensor has an immersion effect correction factor of 1.32.

divide your air measurement by 1.32
1818 PPFD...........not 2400


As to the rest..
https://www.reef2reef.com/threads/par-in-the-wild-at-depth.715641/page-2#post-7421601

 

[Jaebster]

Testing issue in water (assuming you used fresh water). Saltwater is more dense than fresh and seawater has plankton, silts, etc. When you do a water change, save the old water water (of it's clear and not discolored) and try it. I'm sure the par value will reduce than PAR in just fresh water.

 

[oreo54]

Testing issue in water (assuming you used fresh water). Saltwater is more dense than fresh and seawater has plankton, silts, etc. When you do a water change, save the old water water (of it's clear and not discolored) and try it. I'm sure the par value will reduce than PAR in just fresh water.

https://reefs.com/magazine/imitatin...sage-in-a-reef-aquarium-do-we-really-want-to/

 

[cvrle1]

https://www.reef2reef.com/threads/par-in-the-wild-at-depth.715641/
Didnt see that Oreo already posted this link. Oops

 

[alton]

If you want to simulate the sun try a 400 watt metal halide. When I used 250 watt MH Radium lamps in LuminBright Pendants I recorded Par readings of 1800 to 2000 at the water level. Which was about 9" below the fixture.

 

[Sdot]

If you want to simulate the sun try a 400 watt metal halide. When I used 250 watt MH Radium lamps in LuminBright Pendants I recorded Par readings of 1800 to 2000 at the water level. Which was about 9" below the fixture.

My LEDs are plenty bright... i was just curious about the amount of par my tank gets would be equivalent to what depth in the ocean. At 65% im getting over 300 par at the bottom of my tank. This is with the leds mounted 14 inches above the tank. My tank is also a little more than 25 inches tall.