Lux Meter

[dgbnyc]

Hi,
I'm interested in learning more about Lux Meters.
Anyone that uses one & is willing to take the time,,, I'd be much obliged.
How do you use it, what have you learned/gained from its use? Where is the best place to buy one & which type/brand?
Thanks in advance!:)

[rbaker]

^

[wld1783]

I'm thinking about purchasing one also.

With the cost of MH bulbs, I think that one could use the meter to measure the drop in light over time thus replacing the bulb when it actually needs to be replaced. I currently spend $300 every year replacing bulbs every 12 months. If I could extend the bulb life by a couple of months the meter will pay for itself. What I don't whant to discover is that the bulbs may need to be replaced every 9 months...

Bill

[dgbnyc]

LOL, yes on the bulb replacement.
I have had a challenging to me finding them for sale. Don't know if they are all water proof and was told O should look for one that goes up to 100,000 not 50,000.
Any thoughts?

[theearthling]

Originally posted by dgbnyc
LOL, yes on the bulb replacement.
I have had a challenging to me finding them for sale. Don't know if they are all water proof...I just use my meter that I bought for photography. You can get them at most decent camera stores. You definitely would NOT want to drop any meter I've ever seen in the water, but a little spray probably wouldn't hurt if you wipe it off. Someone out there might make submersible meters for scientific purposes, but I've just been thinking about putting mine in about 3 ziploc bags and dropping it into the tank to see what the levels are at various depths.

...and was told O should look for one that goes up to 100,000 not 50,000. I think you're talking about Lux, here. Mine goes up to 1,900,000 Lux. But if you had one that only went to 50,000, you could just stick a piece of ND9 in front of it (neutral density gel), then multiply by two. If you have MH, you'll be reading a lot higher than 100,000 Lux at the surface of the tank, though.

[theearthling]

BTW - If you're planning to use the meter to determine when the lamps are getting old (which I don't even know if you can tell by intensity alone), be sure to clean any glass on your light fixtures first.:D Dirt depreciation is HUGE, and a thin film of salt spray could easily cut the light transmission by 30% - 50%.

[Mako]

I am still kinda partial to the Apogee line of quantum meters. Lux meters are ok, but they don't really give you much useful information for what we are doing.

Apogee (http://mysticreefs.com/reefpics/Acros/pm1_18_03.jpg) makes a quantum meter, the QMSS-ELEC, which has a waterproof sensor on the end of a two meter cable. I like this idea because now I can take PPF measurements in my tank. $229 for the meter is kinda up there though so I may just opt for the sensor and two meter cable and use my digital volt meter for readings. Only $99 bucks this way.

[big tank bob]

The only thing the Lux meter is good for is to read the total output of your lighting. As for MH the Lux output is all most the same for the life span of lamp (20000 hr. or 6.8 years at 8 hr. per day) But the output spectrum does change over time and with number of heat cycles (starts & stops) So a 10000K with a 200 starts does not have spectrum output as a lamp with 5 starts. The only way to tell if your lamps need replaceing is to just do it, or have a Optical Spectrum Analyzer like the Advantest Q8344A.
I can tell you that you can change your lamps for many, many years and not come close to cost of a analyzer.

[wizardgus®]

Something doesn't sound right here. Awhile back in a rather exasperating thread EricB. had told me I should buy a $69 Lux meter and see what my light levels were in different areas of my tank. It seemed imprudent at the time to ask what it measures and how, but I've since assumed it would tell me something important, if only I knew. Are you guys sure this doesn't give any useful info? As far as light intensity? I know it won't give you spectral quality or wave length.

[theearthling]

Originally posted by wizardgus
Something doesn't sound right here. Awhile back in a rather exasperating thread EricB. had told me I should buy a $69 Lux meter and see what my light levels were in different areas of my tank. It seemed imprudent at the time to ask what it measures and how, but I've since assumed it would tell me something important, if only I knew. Are you guys sure this doesn't give any useful info? As far as light intensity? I know it won't give you spectral quality or wave length.

No! But a Lux meter only measures intensity, which is useful to find out how much light you are putting into the tank (much better than useless WPG calculations). I don't know if intensity fluctuates over the life of the lamp in any useful way, so it probably won't let you know when to replace your lamps.

[uryy4me]

So, how does one know if they are prematurely cycling out perfectly good lamps just because of a passage of time (or likewise if a lamp is going bad early how can it be detected before seeing this in a coral?)?

[looser]

I'm interested in a reply to uryy4me's question. Anyone?

[Philip Parrott]

bump