Things to watch for when changing lighting?

[Son Of Skyline]

I'm thinking of swapping my 400w Radiums back to 250w Iwasakis for awhile to see if I can increase growth rates. Is there anything to watch out for, or little things to do to prevent any unforseen problems? Should I decrease my photoperiod an hour or so to acclimate the corals back to the higher lighting? Or am I just being paranoid and have nothing to worry about or nothing I need to change?

Thanks in advance!

[Namscam]

I think you should decrease your photoperiod and add like one hour or so every week to accilimate your corals. Maybe start of at like 6 hours....I dont know if it is necessary to do this because you are decreasin intensity since this is mostly done when intensity is increased, but i would do it just as a precaution

[Aquattro]

Mason, going to Iwasakis from Radiums will likely require some adjustment. Either raise the lights and slowly lower them, or provide layered screening that you can remove slowly (over a week should be enough).
Your BTA will also likely object and hide for a little while, so watch out for unwanted migration into pumps, etc.

[Son Of Skyline]

Originally Posted by reef_raf

Mason, going to Iwasakis from Radiums will likely require some adjustment. Either raise the lights and slowly lower them, or provide layered screening that you can remove slowly (over a week should be enough).
Your BTA will also likely object and hide for a little while, so watch out for unwanted migration into pumps, etc.

Thanks Brad. Didn't realize the effect it might have on the btas. I'll watch out for them.

I can't move the bulbs up or down so I'll probably try to rig up some screening over the bulbs. Would simply reducing the photoperiod have the same effect?


Namscam, actually going to 250w Iwasakis from 400w Radiums in an increase in lighting. Although the Radiums use high wattage, they're actually not as bright as the 6500k Iwasaki

[Aquattro]

Also, reducing the photoperiod may not be enough. If the intensity levels cause too much photosynthesis in the short period, too much O2 can be produced within the tissues and damage can occur. Enzymes normally control this, but if O2 production is greater than enzyme response, you lose tissue and or zooxanthallae. Rigging the timer to go on and off every hour with an increase in the on period is a better way. the layered screen thing is good also.

[Namscam]

it may be brighter but i m talking about par value for intensity because dont 400w have higher par value than 250w

[Aquattro]

Originally Posted by Namscam

it may be brighter but i m talking about par value for intensity because dont 400w have higher par value than 250w

Sorry, you're wrong. A 250w Iwasaki has a lot more par than a 400w Radium.

[apepper]

If you look at the PAR of a 250W Iwasaki vs a 250W Radium on Joe Burgers MH test site you will see that the Iwasaki has about twice the PAR of the Radium for most ballasts. So a 400W radium is probably close to the 250W Iwasaki assuming you will get about 1.6 times the output extrapolating from the 250 Radium to the 400W Radium. The Iwasaki may still be higher with most ballasts.

http://www.cnidarianreef.com/

[Aquattro]

Sorry, the 400w radium on the HQI ballast had about 500 PAR, based on my system. Steve can confirm, but it may be lower. A Iwasaki on a HQI ballast reads 969 PAR, almost double a 400w Radium on comparable ballast. Even on the std. PFO, it measures over 700 PAR, still way above a HQI driven Radium. That radium was also 2 weeks old at time of testing. After a couple of months, the PAR was likely closer to 300.

[Son Of Skyline]

Originally Posted by reef_raf

Sorry, the 400w radium on the HQI ballast had about 500 PAR, based on my system. Steve can confirm, but it may be lower. A Iwasaki on a HQI ballast reads 969 PAR, almost double a 400w Radium on comparable ballast. Even on the std. PFO, it measures over 700 PAR, still way above a HQI driven Radium. That radium was also 2 weeks old at time of testing. After a couple of months, the PAR was likely closer to 300.

Brad, are these numbers comparing the 250w Iwasaki vs the 400w Radium, or the 400w Iwasaki vs the 400w Radium?