Poor mans PAR meters ???

[roland jacques]

Does anyone use a Lux meter to moniter your lighting output?

I was looking at these on ebay any opinions?

To bad none look like they work under water.

http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&rd=1&item=230195536960&ssPageName=STRK:MEWA:IT&ih=013">http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&rd=1&item=230195536960&ssPageName=STRK:MEWA:IT&ih=013</a>
[IMG]http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&rd=1&item=230197095758&ssPageName=STRK:MEWA:IT&ih=013">http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&rd=1&item=230197095758&ssPageName=STRK:MEWA:IT&ih=013</a>
[IMG]http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&rd=1&item=250192405996&ssPageName=STRK:MEWA:IT&ih=015">http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&rd=1&item=250192405996&ssPageName=STRK:MEWA:IT&ih=015</a>

 

[glxtrix]

one would think tho that if you knew what your par was in your tank with new lights, alls you'd have to do is measure the intensity above the water surface and see how that degrades over time. Unless it degrades more thu water than open air?

 

[roland jacques]

glxtrix;105561 wrote: one would think tho that if you knew what your par was in your tank with new lights, alls you'd have to do is measure the intensity above the water surface and see how that degrades over time. Unless it degrades more thu water than open air?

Yeah I agree, it seems that LUX and PAR degrade at the same rate.
I think measurement at different depths can be as related to your water clarity also. So i am not sure that in the water measurement are helpful when seeing if your lights are still strong.

 

[mojo]

Just make sure that you get a LUX meter that goes high enough. I bought a standard one that went to 50,000 LUX (I think) and that wasn't enough for for my 250w DE's...

But as far as I know, yes, the LUX and the PAR will degrade at roughly the same rate. It's not exact, since bulbs have color shifts over time, so a bulb's LUX may stay the same, but have less PAR.

The biggest disadvantage to using a LUX meter to a PAR meter is that it doesn't really show what you need...

 

[dannybradley]

I believe 1 PAR is equal to 50LUX.

Edit-
After a little research, I believe that's an average Danan Riddle found...

Here is Dana's data: Multiply Lux readings by the following conversion
factors to obtain PAR values.
> Sunlight - 0.02000
> Metal Halide Lamps
> AB 150w 6,800 K- 0.02000
> Coralife 175w 10,000K - 0.02128
> Coralife 175w 20,000K - 0.02128
> Coralife 250w 10,000K - 0.01887
> Coralife 400w 10,000K - 0.02041
> Hamilton 175w "True 10K" - 0.01852
> Iwasaki 400w "Daylight" - 0.01754 (using CWA ballast)
> Osram 150w 5,600K PowerStar - 0.01818
> Radium 400w "Blue" - 0.02083
> Fluorescent Lamps
> Hamilton Compact Fluorescents (4x55w, 2 Daylight / 2 Actinic Combo) -
> 0.02000
> Sylvania PowerCompacts (4x96w, 2 daylight/ 2 actinic combination) - 0.01852
> URI VHO Fluorescent Lamps (4x110w, 2 daylight / 2 actinic combination) -
> 0.02083

 

[sammy33]

http://milwaukeetesters.com/english/products/economy_portable_meters/SM700.html">The one that Milwaukee Instruments makes has a waterproof probe. </a> This unit is about $100 so still less than a Quantum Meter which run about $250.

It maxes out at 50,000 LUX so you can only measure up to about 850 PAR (using conversions - Thanks Danny!).

 

[dannybradley]

oops... Dana. The original equation is one he gave during his talk a few months ago. My notes on it are floating around on one of these threads...

 

[cameron]

They probably do decline PAR and LUX in similar fashion but I am not sure you will see a spectrum shift in the LUX measurement. If that is the case, your PAR would drop (or more accurately your PUR I guess) and you probably wouldn't pick it up. Would be a good test to see though. Possible you get the spectrum shift but not enough to matter until the LUX/PAR begin to significantly decline.

 

[FutureInterest]

The real poor man's par meter is Ouling.

He'll measure the par by staring into the bulb. Surprisingly, he's actually pretty accurate.