# Light Testing



## mikekomm (Jan 31, 2011)

I have a few planted tanks and I want to be able to test my compact fluorescent lights to determine when their output has diminished. I'm curious about whether the intensity diminishes or the part of the light spectrum output changes.

I'm looking at two meters but it seems that both of them measure "intensity", not "spectrum".

Milwaukee Instruments MW700 Lux Light Meter

Aquarium Lighting & Monitoring: Milwaukee Instruments Smart Lux Light Meter

Does anyone have experience with this or recommendations?


----------



## Landau (Apr 28, 2010)

One thing you may have on hand is a good digital camera.

Put a white plastic card or other improvised target in your tank at a 45 degree angle, then zoom in so it fills the frame (or use the spotmeter setting if your camera has one) Turn out the room lights and close the drapes.

Now see what your camera meters the exposure as.

Repeat once a month or so using the exact procedure (camera in same spot, algae cleaned off glass, same lens zoom, iso and apeture settings etc)

You'll easily catch diminshed output over time.

I once saw a chart giving lux readings from camera exposure settings (using a mirror pointed at the lights as a target) but I can't find it at the moment.


----------



## EDGE (Aug 24, 2010)

Try this link. If you can find a par meter, that is way better and more accurate for planted tank.

Aquarium Lighting; Kelvin, Nanometers, PAR, Bulb, Watt, MH, LED, Light Basics.

Red light and blue light aren't that bright so lux would not be a good representation of the spectrum or strength of the bulb correctly for horticulture purpose. A bulb can look dim but still has a lot of juice for plants.


----------



## 2wheelsx2 (Apr 21, 2010)

I think the reefers (like Seahorse_fanatic) have an Apogee PAR meter you can rent. You might try that.


----------



## kelownaguy (Jan 1, 2011)

This may interest you.
Construction and Testing of an Inexpensive PAR Sensor


----------

