How high are your LEDs off the water?

[ReeferMadness80G]

seems like I keep bleaching corals with my retrofit LEDs about 7-8 inches off the water. Hoping maybe you guys can share what your doing and if there is a standard. I don't have a Par meter and really don't want to buy one. Just looking for some options

 

[Waterjockey]

seems like I keep bleaching corals with my retrofit LEDs about 7-8 inches off the water. Hoping maybe you guys can share what your doing and if there is a standard. I don't have a Par meter and really don't want to buy one. Just looking for some options

Mine are about 12 inches above the water surface. A lux meter is cheap and can give you a ballpark intensity

 

[Higher Thinking]

FWIW, I have LEDs about 12" off the surface with 24" depth. The variety, intensity, etc. makes it difficult to assess your situation based on other people's setups.

 

[Neil Fox]

One of my tanks is running a 165w black box. I raised it from about 12" to 15" over the water to get better distribution. I also bumped up the intensity also.

 

[saltyfilmfolks]

I use a lux meter to set intensity of the light. Every 5000 lux is roughly 100 par.
The lux at the top of my tank is 40,000 lux to grow highlight coral.
For low light coral id start at 20,000 lux.
Direct summer daylight is 2000 par.
That's 100,000 lux.
Amazon has lux meters today for $13. It's the red one.


Oh yea one of my lights is 16 in off the water in the cube. The 55g the lights are 8in off the water.
Both are set at 40,000 lux.

 

[Bdog4u2]

I have 4 hydra 26 hd's over a 6ft 150 and they're about 5-6 inches above and cranked almost wide open. I use glass lids so they block some of the light since I never cleaned them

 

[mcarroll]

seems like I keep bleaching corals with my retrofit LEDs about 7-8 inches off the water. Hoping maybe you guys can share what your doing and if there is a standard. I don't have a Par meter and really don't want to buy one. Just looking for some options

@saltyfilmfolks hit the nail on post #5

Get a lux meter (or app) now – stop guessing and start measuring!


I would add that the question about height is a math problem. Triangle math.

I am not a math person, but I figured this out!

If you know the amount of area you need to cover (some or all of the surface of your tank, for example) and the lens angle on the fixture, you can compute the ideal mounting height so you have a good place to start.

It's easy if you have 90º lenses
In that case, mounting height = coverage radius.

So for a 48" x 24" (8 sq ft) tank, you'd figure about a 12" coverage radius. Mount your lights at 12".

For other lenses
Say you have 120º lenses over that same 48" x 24" tank. Break it down like this:

    60º
    |\
??  | \
    |  \
90º -----
     12"

Make sense?

And use a calculator like this to fill in the blank:
https://ostermiller.org/calc/triangle.html

Mount that light at about 7" from the water to get a 24" diameter of coverage.

These numbers are very exact and lighting is very subjective, so remember these numbers are a starting point.

 

[mcarroll]

Sorry, didn't mean to slight @Waterjockey on post #2!!!! Sorry @saltyfilmfolks!

 

[Michael01]

@saltyfilmfolks hit the nail on post #5

Get a lux meter (or app) now – stop guessing and start measuring!


I would add that the question about height is a math problem. Triangle math.

I am not a math person, but I figured this out!

If you know the amount of area you need to cover (some or all of the surface of your tank, for example) and the lens angle on the fixture, you can compute the ideal mounting height so you have a good place to start.

It's easy if you have 90º lenses
In that case, mounting height = coverage radius.

So for a 48" x 24" (8 sq ft) tank, you'd figure about a 12" coverage radius. Mount your lights at 12".

For other lenses
Say you have 120º lenses over that same 48" x 24" tank. Break it down like this:

    60º
    |\
??  | \
    |  \
90º -----
     12"

Make sense?

And use a calculator like this to fill in the blank:
https://ostermiller.org/calc/triangle.html

Mount that light at about 7" from the water to get a 24" diameter of coverage.

These numbers are very exact and lighting is very subjective, so remember these numbers are a starting point.

I just want to buy a Lightimetunnel led aquarium light, would like to try this.

 

[ReeferMadness80G]

Awesome! Thanks everyone. Exactly the info I needed : D

 

[Mushroom Boy]

I'd love to get a handle on this as well. Saltyfilm, is this the model you're referring to? https://www.amazon.com/Docooler-Dig...UTF8&qid=1473380915&sr=8-4&keywords=lux+meter

Also, pardon my total noobness, are these submersible?

 

[saltyfilmfolks]

I'd love to get a handle on this as well. Saltyfilm, is this the model you're referring to? https://www.amazon.com/Docooler-Dig...UTF8&qid=1473380915&sr=8-4&keywords=lux+meter

Also, pardon my total noobness, are these submersible?

Yes that's the right one. Just take the reading at the top of the tank. Depending on the depth of the tank and the livestock you set the level.

 

[Mushroom Boy]

Perfect, thanks. I think I'll order one and see where I'm at. My lights are relatively close to the water (Steves LED upgraded BioCube hood). Roughly 2" from the surface and 12" from the bottom of the tank (top of the sandbed).

 

[ReeferMadness80G]

Perfect, thanks. I think I'll order one and see where I'm at. My lights are relatively close to the water (Steves LED upgraded BioCube hood). Roughly 2" from the surface and 12" from the bottom of the tank (top of the sandbed).

That's what I have on a Biocube 14, steves fully loaded sps kit..I've got my lights suspended about 12" above the surface now

 

[ReeferMadness80G]

I use a lux meter to set intensity of the light. Every 5000 lux is roughly 100 par.
The lux at the top of my tank is 40,000 lux to grow highlight coral.
For low light coral id start at 20,000 lux.
Direct summer daylight is 2000 par.
That's 100,000 lux.
Amazon has lux meters today for $13. It's the red one.


Oh yea one of my lights is 16 in off the water in the cube. The 55g the lights are 8in off the water.
Both are set at 40,000 lux.

I got this app from the App Store and I'll screen shot the reading from the surface of my tank, LEDs are about 12" above the surface

 

[ReeferMadness80G]

 

[Salty1962]

@ 9" RMS mounts. T5s @3" legs.

 

[Frop]

Eyeballing it.. My hydra 26HD is 6-7" inches above the waterline. Tank is 20" wide. I just set the height to what I thought looked good then used plumbers tape to set the height. I'm not running the LED at full power either..

But.. I think LED spread, output, water line to coral distance are also going to have some serious effect on how much light a coral is getting.

P.s.
I have a lux meter. Current list price is $20 on that one.

 

[mcarroll]

I'd love to get a handle on this as well. Saltyfilm, is this the model you're referring to? https://www.amazon.com/Docooler-Dig...UTF8&qid=1473380915&sr=8-4&keywords=lux+meter

Also, pardon my total noobness, are these submersible?

I would recommend the one most of us use the has a remote sensor. Search for the "LX-1010B".

It looks like this:

Read this:
https://reeformadness.wordpress.com/2016/09/06/beginners-lux/

Something was wrong with that lux app you tried....can you try another app?

 

[ReeferMadness80G]

I would recommend the one most of us use the has a remote sensor. Search for the "LX-1010B".

It looks like this:

Read this:
https://reeformadness.wordpress.com/2016/09/06/beginners-lux/

Something was wrong with that lux app you tried....can you try another app?

Why would you think something was wrong with the app I tried?