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

[DJ88]

Dana Riddle just posted this on Fishnet...

Interesting..

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 <font size="2" face="Verdana, Helvetica, sans-serif">Hee hee.. So my 250W is better than your 400W.. nyah tongue.gif nyah tongue.gif nyah.. ;)

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

Brad you reading this?

[BCReefer]

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]

Originally posted by DJ88:

Brad you reading this?<font size="2" face="Verdana, Helvetica, sans-serif">No, I'm not!! Never saw it.

[Delphinus]

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]

Hee hee.. So my 250W is better than your 400W.. nyah nyah nyah..
<font size="2" face="Verdana, Helvetica, sans-serif">Hmmmm.. the debate continues..

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

[Achilles]

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]

when exposed to light intensity generated by higher output lighting systems (400-watt metal halides, 4-96 watt PCs).<font size="2" face="Verdana, Helvetica, sans-serif">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]

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]

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

:D

[Troy F]

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....<font size="2" face="Verdana, Helvetica, sans-serif">How's Gary's tank coming anyways?

[Tigger]

I was planning on putting 4 96W PC bulbs (2 10,000K and 2 attinic)over my 108 Gallon tank. Is this too much light for softies and LPS?
My tank is 20 inches deep with a 3-4 inch sand bed.

Should I just put in 2 4ft NO attinics instead of the attinic PCs? I was planning on using the Workhorse 7 ballast. Should I use T12 or T8 bulbs?

[SuperFudge]

Tigger,

I dont believe that is too much light,by a long shot.

My corals just told me not to listen to Dana,so i dont think im gonna. ;)

Isnt some "Inhibiting" just what we want?...
to get the colors we wish ?

I dont disagree that they can be "maintained" under these lower lighting scenarios,but to just maintain them is not enouph.
I have had many sps in low light areas,and the majority of them are brown,due to producing extra zooxanthellea(sp?)to make up for the lower light levels.
This is consistent with mother colonies that are directly under heavy lighting,producing a much nicer color by far.

Ok,Could someone hold this rock up so i can crawl back under it now?

Marc.

[ 14 May 2002, 21:08: Message edited by: Superfudge ]

[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....

[reefburnaby]

Hi,

Isn't a 250W Iwasaki as bright as a 400W MH ? Or am I just confused.

- Victor

[pocilipora]

Im going to be switching to 400watter from my 250 Iwasakis.Im hoping for better coloration but I guess time will tell. Should be done by the weekend.

[canadawest]

Hey Pocilipora, if you're thinking about selling your 250W Iwasakis, let me know. I might be interested in them.

[pocilipora]

Ive got 1-250watt Iwasaki with ballast and 2-400watt ballasts.

[pocilipora]

Just hooked up the new 400watt German bulbs. Man these things are insane compared to the 250 Iwasakis.Oh happy day

[pocilipora]

Well its been 2 months since Ive changed from 250 Iwasakis, to 400 watt 10,000k german bulbs. The tank went through a small diatom algae bloom for about 2 weeks, before things cleared up.
The colors Ive been able to pull out of these corals has been nothing but amazing. I was never able to get these colors with the 250s. Also there are no signs of slowed growth or bleaching by any of my SPS corals. And my Crocea clam loved the change.

[Diomedes]

First of all, "Reduced Photosynthetic Activity" is not necessarily a bad thing. When there is a high degree of light, there isn't a need within corals to have a large amount of zoxanthellae. This is because there is sufficient light to run these little zoxanthellae sugar-factories at high efficincy. Therefor at high light levels there would likely be a reduced photosynthetic activity...the coral will purge itself of excess built up zox that it may have gained during a low light period. This would register on this woman's meter as reduced photosynthetic activity. It is well documented that too many zoxanthellae running at maximum efficiency will poison your corals with the waste products (02-day, CO2-night). Also - measuring photosystem II's byproducts and from there extrapolating an change in Rph (Rate of Photosynthesis) is a difficult thing to do theoretically because of the natural flux of these byproducts. This sounds fishy to me...until I hear more proof we should take this Dana and rocket her off to the sun so she can measure the effects of too much light intensity on human tissues. :cool:

Stephen

[Troy F]

Dana's a dude, dude smile.gif .