Anybody have any recommendations for a good lux meter with a submersible probe?
I'm not aware of any other submersible lux meters.
If you make it $56 I think that Milwaukee is a no-brainer....and these guys apparently have it on sale:
http://www.testequipmentdepot.com/products.htm?item=MW700&ref=gbase&gclid=CMr065WYvMwCFVE0aQodi2cFWA
(
@saltyfilmfolks found this later....just reposting)
I'm not positive, but it may ONLY take readings under water. If so (check the manual), I'd still get a cheapie $15 handheld lux meter for measuring out of water. (A cheap handheld is all I use.)
Also, any good way to convert Lux to Par or Lux levels for various coral types?
The easy, shorthand way I use is based on these rough equivalencies:
2000 PAR = 100,000 lux = Direct Sunlight At Sea Level
That gives you an easy conversion factor of 50.
I.e.:
2,000 x 50 = 100,000
100,000 ÷ 50 = 2,000
That has worked well for me in almost any scenario.
Note: If you haven't read the Dana Riddle articles (only one or two I think) where he talked about lux meters and PAR meters, conversion factors, etc.....you should.
The one nugget I'll pass on is that every lighting system will actually have its own conversion factor. Interesting!
However, as I said, I've found that a generic conversion factor (based on sunlight) is still accurate enough for us in this case.
If it helps, remember that most corals, in general, are not particular at all about lighting levels:
- Anything from 5,000 lux up to 100,000 lux will keep corals alive.
- 20,000-80,000 lux seems to be the "safe range" - meaning that growth is good at the low end but light stress isn't causing major problems on the high end.
- Around 30,000-50,000 lux seems to be a sweet spot. Maybe it's coincidence, but this seems to be the range where most manufacturered LED fixtures max out.
But that's all in general.
Once we're talking about a particular coral, especially once it matures, there are practical considerations. For example, while frags seems almost supernaturally adaptable and resilient, mature corals do not generally respond well to dramatic lighting changes.
If you're setting up a new tank with fresh frags, you may have quite a bit of latitude in deciding what intensity to run your lights. I have a tank I set up that runs at about 14,000 lux. Grows the same stony corals as the main display that gets around 50,000 lux...probably a bit slower is all. I started it with (mostly) fresh frags from the main display.
However, if you're upgrading lights, or moving corals to a system with different lights, you really want to forget about your choice....instead, the idea would be to match the old tank's intensity as closely as you can. You can try to match the color too, but you should set color how you like it in my opinion. As long as you pick some color combo that's at least vaguely "reef-like", it'll work and the numbers will be fine. We're not being precise enough for that to matter, nor is there a need to be.
A cheapie lux meter will get the job done in both scenarios.
My guess is that, within the scope of that shadow, you're measureing 80-90% of the light hitting that spot. Good enough!!)
