A practical, affordable PAR meter?

revhtree · Jun 23, 2014

Interesting.

SantaMonica · Jun 23, 2014

I've seen the sun calc before.

Shtiff1 · Jun 23, 2014

mcarroll said:
10,000 is the low end for "full sun" conditions. 30,000+ is "direct sun".

So, unless you are keeping low-light corals, I'd suggest doubling your light output and see how thing go when you're close to 10,000. For reference, I think my tanks run at about 14,000 lux and 60,000 lux respectively and both grow the same corals.

Make any increases gradually over at least a week - a few weeks would be better.

-Matt

Yes that is what i did. I am now using 3 - 165 watt led's. I got a Par meter and tested and now I get 225 at the sand bed no problem. First day was yesterday and I set them to 100 Par at the sand bed instead of 40, and will increase to 200-225 in a week or more. Thank you.

mcarroll · Jun 23, 2014

SantaMonica said:
I've seen the sun calc before.

Mine came in the mail (early!) today. With luck I'll have a test done by tomorrow evening.

-Matt

mcarroll · Jun 26, 2014

Well, I've run a couple tests outside and it seems to work as advertised.

It may take a while for me to report back again as I still have some outdoor spots I want to sample and each test is 12 hours, but I'll run it under the aquarium lights and see what it reports. (Maybe we'll get a cloudy/rainy day and I'll use that to test inside.)

-Matt

reef lobster · Jun 27, 2014

get a seneye its perfect

mcarroll · Jun 28, 2014

reef lobster said:
get a seneye its perfect

Read from post #13, on.

-Matt

Shtiff1 · Jul 2, 2014

This might be of use to someone.

mcarroll · Jul 2, 2014

Shtiff1 said:
This might be of use to someone.

Interesting! Sounds like that could be a good enough approximation for those needing to compare with PAR numbers from another source.

Where's this from, btw?

-Matt

prsnlty · Jul 2, 2014

Interesting read. I have no one to borrow a Par meter or Lux meter from and may order the meter you suggest on the 1st post. I have trouble keeping sps for longer than a few months except montis. Wondering if they are getting enough light. Over a 125g I have 2 ai sol bues and 2 24" PC in the middle and on the outsides I have 2 T5s, 1 is ATI purple+ @ 60"L and the other is ATI Coral+ @ 60"L.They are located 12 off the surface.

cope413 · Jul 2, 2014

those calculations seem about right based on the numbers I get from my Seneye. The difference is probably a rounding issue as they're within 5%.

Following along to see your numbers. I'm sure there's an easy formula to turn my Lux, Kelvin, and Par data into "full sun conditions", "partial sun" etc...

Shtiff1 · Jul 3, 2014

mcarroll said:
Interesting! Sounds like that could be a good enough approximation for those needing to compare with PAR numbers from another source.

Where's this from, btw?

-Matt

http://www.advancedaquarist.com/2013/2/equipment

Shtiff1 · Jul 3, 2014

I don't know, I'm still at a loss. Just took readings with just blues. With Par meter ( apogee sensor with volt meter ) ; 350
Beecam light meter on phone ; 12500 lux. Then you throw in the chart and you have 3 different readings. Rrrrrr

mcarroll · Jul 3, 2014

prsnlty said:
Interesting read. I have no one to borrow a Par meter or Lux meter from and may order the meter you suggest on the 1st post. I have trouble keeping sps for longer than a few months except montis. Wondering if they are getting enough light. Over a 125g I have 2 ai sol bues and 2 24" PC in the middle and on the outsides I have 2 T5s, 1 is ATI purple+ @ 60"L and the other is ATI Coral+ @ 60"L.They are located 12 off the surface.

If you have a smartphone, try a free lux meter app. Also consider a hand-held lux meter (<$20). You could also get the PAR calculator I linked here (Sun Calc), but I haven't had a chance to test it on the tank yet, so you'd be a guinea pig like me...tho I don't see any reason it won't work as well there as it does outside....we'll see.

cope413 said:
those calculations seem about right based on the numbers I get from my Seneye. The difference is probably a rounding issue as they're within 5%.

Following along to see your numbers. I'm sure there's an easy formula to turn my Lux, Kelvin, and Par data into "full sun conditions", "partial sun" etc...

The trick is finding the info.

Lux is well known and established. Look no further than the Wikipedia article on lux for the exact info you are describing....or any of a dozen other links that will come up on a Google Seach for "lux".

The first thing you learn about when searching for "PAR" is that the measurement numbers you see aren't very standardized in their units of measure. Two of the possible units for full daylight (IIRC) are 400 umol and 2000 w2. I may have those incorrect and backwards, but it's in the right park and I think I named the units right. If you find more info than this, please post it.

Shtiff1 said:
Aquarium Equipment: PAR Meters and LEDs - How Accurate are the Measurements? A Comparison of Three Meters and Lux to PAR Conversion Factors for LEDs ? Advanced Aquarist | Aquarist Magazine and Blog

Great link! Thanks!

-Matt