Lighting level above tank

[Anonymous]

So I made the switch from XM 15K to XM 10K on my 125 gallon reef. The fixture is a PFO 72 with 3 250watt halides.

My question is where should I start when I hang it? As it is it was 10" off the top with the 15Ks

Oh yea I made the switch to get more growth out of my sps corals.

Thanks

 

[Ben1]

IIRC there is a huge difference in par between those two bulbs, and since the 15ks were old going to new xm 10ks would shock the corals if you just switched so either raise the fixture and slowly lower it back to position or use on of the other methods. Other methods would be like using several sheets of window screening and removing one every few days.

 

[Anonymous]

Thanks

I was looking at numbers. Like how far to raise the hood? 18" 24" or less...

 

[mr_X]

i disagree with raising the fixture. i don't think a little air is enough of a light diffuser to make a difference. i can say this from experience.

i suggest shortening the photo period and using the screen method

 

[SnowManSnow]

i agree with x. shorten period to 4 hrs add a lil each week till u are back around 7 hrs.

b

 

[mr_X]

my zoos still fried with new bulbs and a 4 hour photo period. i'd use the screens to diffuse some light.

 

[SnowManSnow]

i didnt have the issue .. even though i went from a 14k to a 10k lamp i dropped from 400w to 250w.

b

 

[mr_X]

see, i went from a 400 watt ebay cheapo bulb to an ushio 400 watt 14k, and my corals acted like vampires at dawn 8O

 

[das75]

When I've changed bulbs or wanted to acclimatize coral or clams for light, I've placed eggcrating across the euro-bracing with sheets window screen on to of it. Every couple of days remove a piece.

Little off topic but wondering of the height people run their bulbs?. When I was making my canopy was thinking either Hamilton or PFO pendants so e-mailed them both. From Hamilton for their Reefstar pendants they recommended 8" above water, from PFO and their mini-pendants they said 5 ". I had indicated was planning 250W DE pendants.

 

[mr_X]

the bulbs themselves are a foot and a half off of the water on my tank. i use lumenarc minis, so i think they spread better there.

 

[Ben1]

I use a pfo hood and have in the past years just raised it from its normal postition an additional 10 inches, it reduces not only the distance but the amount of light reflected into the tank. Since I dont have a fixed position hood (its hung by chains) that has worked for me in the past but i guess ymmv....

to each there own there are more then one way to skin a cat lol

 

[ChrisRD]

Raising the lights and/or the screening method is what's always worked best for me. Personally, I've not had much luck with reducing photo period. If it's a big change in intensity, I find even a drastic reduction in photo period can still result in bleaching (unless it's combined with one of the other two methods...).