PAR (in microeinsteins); whats your Max and Min

[Opsanus tau]

Wondering if someone would share their tank readings, top to bottom,
I'm setting up a few new systems and would like to get a few different numbers, I'm using an Apogee Quantum Meter, I know they are considered a toy in the scientific community, but it seems to get you in the range.
I remember a thread a few years ago (probably Sanjay) that showed a tank or two with the readings marked on the glass

[Opsanus tau]

How about just a single number,(like putting your probe right next to your favorite coral,) I'm mainly interested in the variety of light regimes and how much they seem to vary from tank -to -tank (especially for sps corals).
Thanks-O.tau

[ReefTycoon]

well I can comment here ... I also own an Apogee Quantum meter .... (i think any serious SPS keeper should really buy one...) and i also think they are just fine for our applications ! no need for anything too fancy

let's see ...

2 x 250 watt HQI 14K Phoenix powered by Lumatek ballasts
8" off the water's surface and then 18" from the water's surface to substrate
(I also run carbon 24/7)

water's surface = over 1000 µmol m-2 s-1

1" below 700 - 800µmol m-2 s-1

6" below 400 - 500 µmol m-2 s-1

12" below 300 - 400 µmol m-2 s-1 (some spots i get high 200s)

Substrate just over or under 200 µmol m-2 s-1 so say like 190 - 250 µmol m-2 s-1 roughly

hope that helps you out some .... think you need some more input lol
some people don't think PAR matters ... i do

[Opsanus tau]

Tycoon, Thanks!
Do you Keep Mainly Acros in this tank? and what is the most intense reading one of your sps corals are receiving(coral closest to your lights, and what acros in particular (I'm interested in) do you have low in the tank?

I think( I'm going to go take some readings right now) that I am running allot! less light,) I will get back to this either tomorrow or the next day (in-laws in town )

I had my meter made, and calibrated with a 100' cable,..I take it out to my nursery site( @36' deep) and to different patch reefs just out in front of our home and you would be surprised at how varied my readings have been, I think I could honestly say that I have NEVER had the same reading at the same reef(at the same time of day).-Dave

[ReefTycoon]

I just read this now! i don't go online on the weekends, only during work hours LOL ... so give me a bit and later when i have some down time i'll get back to ya .... !

ok i'm back

I can imagine you get all kinds of different readings ... in the same spot i get tons of different ones just because of water ripples and such ... but i've never taken any readings in the sea so i would imagine they don't get that kind of effect so deep ... must be different reason .. ie clouds, time of year ... although i'm only speculating you would have a better hypothesis about why in the ocean i'm sure lol

I keep mostly SPS ... one of my Acros that has been with me from day 1 is about in the 12" from the water surface area ... I can go home tonight and get a reading and tell you exactly around what it is getting and i'll even post a pic of it so you can see it's color ... but my camera sucks so ... well ... you'll see what i mean when i post them .... i can really only take pictures with the flash through the glass when the lights are off ! ... don't ask i can't figure it out i'm no photographer !

besides that most of the other Acros i have are still sitting in the upper 6 " of my tank in a frag rack and they haven't been mounted yet ... and i bet they are being blasted right there lol I actually haven't taken a reading from my frag rack so i will do so there too if you like ....

I have a few Millis that are pretty much soaking it up at anywhere from 300 - 500 µmol m-2 s-1
I'll have to double check that too lol .... I only really use the meter now and then .... a lot when i first got it, but only now and then once I established what readings i was getting when the bulbs where new ( I just bought it like 6 months ago so ... )

most others are Montis and a Hydno .... basically i have 3 LPS and 1 softy in a 75 gallon tank all the rest is SPS of some kind .... I even cleared a bunch of real estate to make room for more Acros and Millies .... i did something really noobish that we wont mention and had a little misshap that needs fixing lol shshshs ...

[ReefTycoon]

Ok didn't get pics taken because i was lazy after work but i did get some new measurements !

ok just about every Acro colony i have sits in PAR values of.... let's see.... at the lowest part of the biggest colony i have (it's about 10" to 12" tall) it averages about
290 µmol m-2 s-1
and that is being shaded by the top .... with the pumps on (figured this made the most sense to take them this way)

at the top of this large colony i get readings that jump from about
350µmol m-2 s-1 to 480µmol m-2 s-1 (489µmol m-2 s-1 was the highest it jumped) now when this Acro grows another few inches it's growing tips will be in the low to mid 400µmol m-2 s-1 to low to mid 500µmol m-2 s-1

so if you want say the mean of that would be about 415µmol m-2 s-1

and a few colonies i forgot about

I have a beautiful hairy yellow with bright blue tips Acro that gets bathed in the 300µmol m-2 s-1 to approximately 400µmol m-2 s-1
and a Blueberry Acro that is about the same ... a little less because it is off to the side ....

my Frag rack (which is the main thing i was curious about seeing as how i haven't taken any measurements of it yet) To my surprise wasn't as intense as i thought with readings only in the upper 200µmol m-2 s-1 to lower 300µmol m-2 s-1.... hmmm I'll have to play with that

stupid reflectors ... don't have very good spread and sit probably too close to the water's surface ... don't know why parabolic reflectors are just now starting to get noticed in the Reef hobby world... they have been proven winners in indoor horticulture when it comes to spread and reflecting as much light as possible .... but I'm ranting ... that's a different subject all together .... lol

of course you can take averages of all these readings if you like. Figured I'd let you do the math lol
and of course ALL these measurements jump up significantly when you shut off the circulation pumps!
which i do do when i do water changes and sometimes it's like that for and hour or so !

hope that was good enough for ya!

[ReefTycoon]

I was looking for this article .... if you go by what is in this article ....

my acros are way .... way under these recommended values! lol

Advanced Aquarist's Online Magazine - Lateral Lines: Classification and Terminology For Reef Aquarium Lighting