400W MH's inhibiting Photosynthesis......

DJ88 · #1 05-13-2002, 06:02 PM

Dana Riddle just posted this on Fishnet...

Interesting..

Quote:

All,

I'm in the initial stages of collecting data with my new PAM meter. In essence, this instrument is a 'photosynthesis meter' and collects information about Photosystem II performance under various light intensities.
Interestingly, some of the corals that we'd expect to do well under 'strong' lighting actually show reduced photosynthetic activity when exposed to light intensity generated by higher output lighting systems (400-watt metal halides, 4-96 watt PCs).

Not only do higher light intensities 'aggravate' photosynthesis (in these cases, anyway), but it is possible one is also throwing money down the drain due to lamp/chiller operational costs.

Dana

Hee hee.. So my 250W is better than your 400W.. nyah [img]tongue.gif[/img] nyah [img]tongue.gif[/img] nyah.. ;)

Seriously tho.. This is an interesting thing to hear.

Brad you reading this?

BCReefer · #2 05-13-2002, 06:22 PM

I read that many corals actually spend a great deal of energy protecting itself from the high intensity of the sun. maybe this is why the 400W lighting is not as good as the 250W, depending of course on the depth of your tank.

Patrick

Aquattro · #3 05-13-2002, 06:45 PM

Quote:

Originally posted by DJ88:

Brad you reading this?

No, I'm not!! Never saw it.

Delphinus · #4 05-13-2002, 07:03 PM

Interesting to see hard evidence of a potential point of diminishing returns.

The one possible caveat I can potentially forsee is this. I thought that, at least in some cases, we see more vivid coloration in corals under higher intensities as compared to under lower intensities, because the corals are using pigmentation is a means to reflect AWAY unneeded/unwanted wavelengths. Without this "extra unnecessary light" growth may be OK or even optimal, but the colour of the coral is a sort of dull tan or brown. More interesting to see the pinks and the purples and the greens and so on.

But, considering I just switched to 2x250W's from 2x175's, I'm happy to learn that I might not need to go to 2x400's down the road (unless I go with a deeper tank, of course...) :D Whew, dodged a bullet there! :D ;)

Silverfish · #5 05-14-2002, 12:39 AM

Quote:

Hee hee.. So my 250W is better than your 400W.. nyah nyah nyah..

Hmmmm.. the debate continues..

Boy am I glad I have a 250 W Iwasaki :D

Achilles · #6 05-14-2002, 02:31 AM

Well one can always raise his or her 400 watt halides higher above the tank. In this way they can actually control the amount of light reaching the coral to a much greater degree than someone using 250's! :D

of course that only works for PFO canopy users, (like myself) and pendant users.

Cheers!

StirCrazy · #7 05-14-2002, 02:39 AM

Quote:

when exposed to light intensity generated by higher output lighting systems (400-watt metal halides, 4-96 watt PCs).

Is Dana sugesting that this "Saturation level" can be reached with 4-96 watt PC's. if so this would also sugest that they put out MORE usable light than a 250 watt MH. Also that this amount of PC lighting is usable for high light Corals. If this is true you can get rid of MH lighting and lower the heat transmision to your tank.

just a though

Steve

Aquattro · #8 05-14-2002, 04:16 AM

Jeff, good point. My lights are about 9" from the water. SO that reduces the lighting somewhat. And after I get my 180g, they'll just get moved lower. Glad I don't have those wimpy 250w bulbs! :D

BCReefer · #9 05-14-2002, 12:14 PM

I guess I am luckier than all after I get my compacts with a lowly 175W MH.

:D

Troy F · #10 05-14-2002, 09:11 PM

Quote:

Originally posted by Mushroom Boy:
Interesting for sure. I'll have to bring this thread to a friend of mine's attention. He's about to pump 1800 watts (one 1000 watt and two 400 watts) into his 170 cube....

How's Gary's tank coming anyways?