hqi metal halide?????

[Ritteri&Bubbles]

Sorry Jeremy but Sanjay only contradicted himself. His only statement made here contradicted his own words from 2 different articles he wrote.

In Sanjay's OWN words from his OWN ARTICLE on page 69 of the 2002 Annual of Marine Fish and Reef he quotes:

Using a reflector, this value can easily be increased by another 50 to 75 percent(depending of the quality of the reflector design).

This was in direct reference from him after stating that all bulbs were tested at a distance of 18 inches from the sensor WITHOUT reflectors.

I have a pretty good feeling that Sanjay didnt spend very much time reading this post,and that his assumptions posted were completely off base, as his own words are now directly contradicting what he himself said in the article. I suggest Jeremy that before you go quoting anything that Sanjay said here in this post, that you spend a few moments, pick up the magazine with the article in question and read for yourself. Then come back to this thread and re read what Sanjay posted. If I am misusing Sanjay's own studies then he should step up to the plate and clarify why his latest article states what it does. As for information used, it goes a bit farther than Sanjay, but of course alot of its based off of his own work. Nobody else has really posted anything truely meaninful. But irradience(lux) and PUR/PPFD values do not go hand in hand this is a fact I dont need Sanjay for know. Especially with the tool you used for measurement.

 

[esmithiii]

On the Earths Equator the minimum and maximum "LUX" value is from 115,000 125,000 at midday per square meter on the oceans surface, with the yearly average about 75,000 LUX. With the daily average from sun up to sun down closer to around 50-60,000 LUX

So by your "lux" calculations at 8" above the waters surface a pair of 150 DE bulbs would actually give off a very close rendition of the suns irradiance. On tanks with dpeths of a meter or less(99 percent of the tanks used by hobbyists are less than a meter deep)it would almost seem that folks using Iwasaki and DE 250 watt bulbs are literally using too much light for the average aquariums with a maximum depth of 1 meter, which may show that more isnt always better(yet another argument).

Where is Galleon when you need him?? My understanding is that 400W iwasaki 6" off the water would be much less than mid-day sun on most reefs.

Ernie

 

[Anonymous]

A 400 watt Iwasaki running on Magnatek ballast and with a reefsun fixture 6" off the water (these are the specifics of the numbers I have) runs average 80,000 lux at the water's surface, with astronomical falloff underwater. Ritteri&Bubbles' numbers for average max and average lux numbers are a far cry from what I am aware of <scratches head>, ie: 100,000 lux maxes often occuring during a sunny day at several meters in depth in the tropical Pacific, not surface.

 

[Ritteri&amp;Bubbles]

Just to clarify my info and where it came from: Modern Coral Reef Aquarium, Volume 1. from page 200 through 217. On lux values at the equator of the earth, taken on the oceans surface per square meter. I do believe I gave a range too didnt I?? And lux values fall off at around 55% at the 1 meter depth.

And the concencus seems that this is a very respectable book. I am sure that there may still be small discrepancies, but I am sure I am not too far off.

 

[Anonymous]

I'm not too sure, much of the literature I have read points to higher averages and ranges. I don't have it onhand, so I won't contend the point further. Either way, the saturation point for many shallow specimens of Acropora sp., Stylophora sp., Pocillopora sp., etc. is 100,000+ lux. So, you still can't provide too much light for many many species of scleractinia.

 

[saltshop]

Either way, the saturation point for many shallow specimens of Acropora sp., Stylophora sp., Pocillopora sp., etc. is 100,000+ lux. So, you still can't provide too much light for many many species of scleractinia.

Really, got references for this? Everything I have read points to even the in-shore stony corals that are exposed at low tide having saturation points of around 20,000-30,000 lux. Some references for you:

Halldall P. Woods Hole Biological Bulletin (1968) 134:411-424
Barnes DJ, Taylor DL Experimental Marine Biology (1973) 24: 284-291
Scott BD, Jitts HR Marine Biology (1977) 41: 307-315
Falkowsky PG, Dubinsky Z Nature (1981) 289: 172-174
Sorokin Y, Coral Reef Ecology (1995) p. 314
Borneman E, Aquarium Corals (2001) p. 328
Borneman E. Pers Com

It is well known that corals in shallow biotopes effectively "shut-down" throughout midday and only resume photosynthesis as light levels drop in the early evening. I would be interested to see anything that states they saturate at 100,000 + lux.

 

[Ritteri&amp;Bubbles]

Here is a nice little comparision between a 920 watt HQI setup vs. a 300 watt DE HQI setup. http://www.reeftalk.com/ubbthreads/show ... o=0&fpart=

 

[Anonymous]

Some of these high lux readings on the bulbs can be suspect. I have been playing with mine over the weekend and noticed a few things... mine is only rated for 0-50,000 lux. If you read it incorrectly you can get higher readings but they are false. My "correct" readings that I took over the weekend are as follows:

New 100 hour old, 400W 10K Aqualine = 34,250 lux
2 year old 400W 5500K Venture = 27,500 lux
New 100 hour old 150W 10,000K BLV-Licht (Ushio) Double Ended = 38,450 lux
New 100 hour old 250W 10,000K Aqualine Double Ended = 46,250 lux

I don't feel like firing up a 400W Saki right now, but I would expect it to be comparable to be around 40,000 lux or so but thats pure speculation on my part.

When my brain is less fried I'll have to reread this thread and post comments.

 

[JeremyR]

Tom,

I've known several people who have lux tested 400w sakis and it's always been in the 80000-90000 range, except for the one bum bulb I have.

 

[Anonymous]

Jeremy - well I've been able to create similar numbers myself until I went back and looked at the specs of my meter (Lutron LX-102) and noticed that it is only rated for 0-50,000 lux. I then realized that I was reading it incorrectly, however if they have 100,000 lux meters I'll take their word for it. I'll see what I can get from one sometime later.

By the way I just noticed I didn't post the distance of measurement for my numbers above, I really am out of it today heh, all those were taken 4" from the bulb.

I will say that IMO PAR isn't automatically more just because of the higher wattage, because emission curves aren't the same. However saying that, we also don't know squat we are arguing over 2 numbers of tests conducted on single bulbs and not multiples. I will be loaning Sanjay a few bulbs and fixtures this summer so hopefully we can have some more definitive testing done.

 

[Ritteri&amp;Bubbles]

I also think that different reflectors should be loaned too to see the differences between them using the same bulb and ballast.

 

[jamesw]

Reflector performance is being investigated for a future article in Advanced Aquarist.

Cheers
James Wiseman