Do 400 watt bulbs do more harm than good?

[JPMagyar]

A recent discussion in another thread brought to light an article I had not previously seen discussed:

How Much Light?! Analyses of Selected Shallow Water Invertebrates' Light Requirements

By Dana Riddle

Personally I have switched from 1000 watt bulbs to 400 watt bulbs to 250 watt bulbs, and my tank never looked better than it does now under 250 watt illumination.

So - Are 400 watt bulbs doing more harm than good in this hobby?

(If there is a thread already beating this dead horse that is current please post a link and I will gladly join the fray there )



Thanks as always,


Joe

[Rickyrooz1]

Interesting. . . .

[KingDiamond]

Originally posted by JPMagyar
A recent discussion in another thread brought to light an article I had not previously seen discussed:

How Much Light?! Analyses of Selected Shallow Water Invertebrates' Light Requirements

By Dana Riddle

Personally I have switched from 1000 watt bulbs to 400 watt bulbs to 250 watt bulbs, and my tank never looked better than it does now under 250 watt illumination.

So - Are 400 watt bulbs doing more harm than good in this hobby?

(If there is a thread already beating this dead horse that is current please post a link and I will gladly join the fray there )



Thanks as always,


Joe

I would suppose that it depends on what you put in your tank. If you have high light corals (SPS) that are found on the reef flats then, they will love the intense illumination of a 400W.

[JPMagyar]

Actually, that's one of the aspects that I found interesting about the article. The research seems to hint that the illumination from a 400 watt bulb may actually cause photoinhibition even in high light loving SPS. In addition, I have seen several posters on RC arguing that 400 watt bulbs are in fact too intense. Personally I find the idea to be a question of application. Two of my favorite tanks in the world, the Oregon Reef, and the Greenwich Aquaria both use numerous 400 watt bulbs, but those reefs are exceptionally large, and may not be a fair comparison. Given my own recent experience with fabulous growth and coloration using 250 watt lighting, I'm beginning to think 400 watts really is "too much" for the average home reef. In all fairness I should add that I am driving my bulbs with PFO-HQI ballasts that overdrive the bulbs such that their output is only slightly less than a typical 400 watt bulb and ballast combination. Still - for a tank less than 30 inches deep why do we need 400 watt lighting?


Just wondering out loud


Joe

[dragonforce]

I run a 175w SE with about 40 watts of actinic t5. My tank is 24 inches deep. Looks great!

[pbukow]

I definately think that there is a limit to the amount of light any photosynthetic organism in the world. As far as i know, there is a Photosynthetic Saturation max that can be achieved and anything after that is superflous. I am no expert on this subject by any means, I'm just regurgitating what I've heard and read.

IMO, I think 400watts is excessive for almost any "normal" reefer's needs. Granted, grow out systems and reef farms may require such a large amount of lumens to light a large amount of animals, but other than that, why would you want to oversaturate your zoaxanthelle?

[Chihuahua6]

400 watts are only "needed" in tanks 30" + deep unless they have a ton of blue spectrum in them. In this case you may need to up the wattage to get the same growth results as you would in say a 250 watt 10k bulb. There are so many other variables of course but in general I believe more times than not 400 watt bulbs are used unnesessarily in shallow aquaria.

[musty baby]

Uh, let's not pass over the fact that they were using 400w Iwasaki "daylight" bulbs, which I take as being a 6500K color temp. There's far more photosynthetically usable light from a bulb of that type than the 400w 14k-20kK bulbs that are used on most reef tanks.

On top of that, most corals are not grown 12" under a 400w metal halide. There's a great deal of volume beyond that depth in most aquariums, forgetting the fact that most people run their metal halide bulbs 8+ inches off of the water.

[carib]

i am not an expert,but been keeping SPS under 250w with good results for a last few years.imo the answer here is yes and no.For most corals that we are trying to keep,250w are more than enough,BUT not for all.I was amazed what 400w did for some of my very admired pieces as growth and coloration,that 250's was simply not enough.Have to mention here that I am on 20K rout,so choosing right ballast and kelvin 250w bulb(XM 10K,evc 10k,AC 14K..)most on HQI can be equaly benefitial to 400w 20K BULBS on electronic ballast.So to say we don't need 400's because we can keep everything alive and growing under 175w iwasaki 6500K,not an answer for me.GUILTY OF CONSUMING ?0000WATTS OF ENERGY to light my reeftank?=YES.There is no other option,at least today.

[shelburn61]

Recent improvements in nutrient levels and water clarity have a big effect as evidenced by the trend among barebottom reefers to reduce photoperiod even with 250w. I think 400s certainly have applications in larger tanks though...

[JediReefer]

Interesting...

I was wondering the complete opposite a few days ago..."Will 400w be enough for a 24x24x25 tank?"

I guess it may be too much.

It is a hard decision being that the price difference for a lumenarc 3 400w and 250w with icecap ballast is only $20.

[gliebig]

I'm looking into lighting for my new 240gallon tank. Dimensions are 60"x36"x25". I'd like to keep lighting simple and was thinking of just using (2) 400watt bulbs on lumenarcs. It'll be a mixed reef,primarily soft corals and lps.
What do you think?

[JPMagyar]

Well I'm sure everyone will have a recommendation, but considering you're plan, my extremely biased opinion would be two 250 watt XM 10ks on PFO-HQI ballasts supplemented with T5 or VHO actinic . . . but that's just one of a myriad options.

Personally, I would NOT go 400 watts for a 25 inch deep LPS/softie tank.

Edit: I just wanted to add that any of the "Euro Style" fixtures with DE 250 watt bulbs and T5 supplementation would be simple, attractive, and highly effective as well.



Joe