Updated - Reef Lighting Test

[Anonymous]

I have just updated my Reef Lighting Test page


synopsis

I suspect one of the most hotly debated subjects in Reefkeeping is Marine Reef Lighting. I have been using 400 watt, 10KK Ushio lamps for a long time. I love how white the light looks and feels. I drive them with both PFO HQI ballasts as well as standard PFO ballasts.

Many of my friends in this hobby swear by the Iwasaki 6500K bulbs. I have seen incredible growth in tanks lit by both types of bulbs. We know from Sanjay Joshi's Tests that the Iwasaki bulbs produce more par. The question is.... Which bulb produces the most growth and coloration in SPS corals.


My experiment will be quite simple.

I have several propagation tanks that are plumbed together. In essence, the water parameters of these tanks will be very similar. I have installed new bulbs over all tanks in April 2001. I have allowed a 2 month break in period for the bulbs. On 5/20/01 I made 2 frags of 7 different SPS corals. I attempted to make each frag of each specific coral as similar as possible in both height and girth. I have placed each frag in a similar spot in 2 tanks. One tank is being lit by a 400 watt, 10KK Ushio lamp, driven by a PFO HQI ballast. The Other by a 400 watt, 6500K Iwasaki lamp, driven by a standard PFO ballast.

 

[SPC]

Brian, thanks alot for this study, this is some solid data.
Steve

 

[chris_h]

So which bulbs was better? I looked at the pictures and could not tell much of a difference.

 

[Anonymous]

From the growth rates there is no appreciable difference. The only major difference from what I see is on the coral set called "Green digitata" which showed a slightly faster growth rate under the 10K bulb than the 6500K. Otherwise they look essentially the same.

So if I was bulb shopping and couldn't make up my mind I would pick what looks best to you and what best suits your wallet.

 

[2poor2reef]

Very nice Atlantis. Seems the green digitata shows the most difference, with the growth under the 10k significantly better than the 6.5K or am I reading it wrong? The others seem too close to call or I can't make out the ruler very clearly in the latest shots. It's also interesting that there were cases where the 6.5K frags were lost but the 10K frags survived. Is there an explanation for that or do you think lighting played any role? Are the two systems still as equivalent as they were back in May, ie. still share the same water column? Are the water flows approximately the same in the two systems? This test will only get more informative over time.

 

[MiNdErAsR]

Interesting that everyone is seeing something different then what I saw. I thought there was more noticable growth under the 6500°k bulbs then the 10,000°k bulbs by a count of 3 to 2. Maybe a case of people (myself included) seeing what they want to see? Perhaps more time is needed before any significant differences will be clearly visible.

 

[JeremyR]

It should also be noted that he's running the 10kk on a HQI ballast, which most 10kk users are not, and this is probably significant IMO.

 

[Iron]

that test just shows 6.5k won't blow away 10k= 6.5k has more par. But how much par does ushio put out? And are all 10k created equal?? Now all being equal i still use 6.5 cuz I have enough left over to buy 3 vho 110w but with 10k you maynot need that many. I still figue its more lighting = good. I wonder if the bulb life is shortened? i would like to see the growth 1 1/2 yrs from now.