[Samper]

I used an Apogee Par meter
From the 20 gallon
Hamilton 14k 2 months old

From the 75 gallon 6 54w T5's
2 Actinic
2 11k
2 65k
All less than 3 months old

These pics are old but you get the idea
What do you guys think?

[Samper]

Are these readings good.....bad.....normal?
Should have put this in the lighting section I guess. Sorry guys and please move if needed.

[Samper]

It seems like I may be way overdoing it on my 20 gallon.... and about normal on my 75 according to some articles by Sanjay. Normal range I see with the 250w de bulbs is around the 100 to 130 range....but that's in PPFD..
I don't know what that is or if I even tested for the same thing. Can someone enlighten me as to what these readings this par meter gave me mean?

[GaryZ]

Will someone answer this man and enlighten us both.

[Samper]

Yeah Gary you tell em!!
I haven't been around much lately to chat cause I'm carrying 18 college hours and working....maybe I should post more or something.

[Reefland]

Well I am no lighting expert but I don't think your corals will reach photoinhibition (photosynthetis no longer occuring) and probably still haven't come close to their saturation point. Was the 1980 reading below the surface?

[Samper]

No the 1980 was taken right at the surface and thats actually the last number the meter registered before the screen changed to a 1. I guess I exceeded what it would read at that point.

[Poseidon]

I so WISH I could help you! I have no clue how to discern those readings. But I am awaiting someone who can, just like you and Gary!

[zhenya]

Chuck,

The only thing I can offer you is to get a book by Dana Riddle "The Captive Reef". It has some very good information og lighting reef aquarium and photosynthesis of corals. FWIW, different corals require different light intensity and reach photoinhibiton at different PAR as well.
In general, if you'd measure amount of light that corals would recieve in nature, you'd find it at about 10200lux. To convert lux to PAR...

Maetal Halide PAR = Lux divided by 75
10K MH PAR =Lux divided by 30

What I am trying to say, Chuck, you have nothing to worry about with your lights on the 20g tank.

[kevinpo]

Hello,
I like to see about 400 PAR on the meter at 16" below the water surface with the bulb mounted at 9" above the water surface (for high light SPS corals). The 400W DE bulbs and the 400W SE bulbs will do this when driven by an HQI ballast. I haven't played around much with the 250W bulbs because the price is about the same and 80 gal is the smallest tank I have owned.
The bulbs I have tested that meet this criteria are:

XM 10,000K SE
Crystal Star 10,000K & 20,000K DE
Ushio 10,000K SE
Reeflux DE
Reeflux SE

I have only tested one bulb of each and MH bulbs are famous for varying from bulb to bulb. All the bulbs were mounted in a PFO pendant, Coralvue pendant, or PFO parallel reflector. The reflector is critical in controlling the spread and intensity of the light.

Regards,
Kevin