changing out the light

[Jacksparrow]

Aloha all, I am running a 400w 12k reeflux bulb on (Lumenarc mini) my mixed coral system and I think it's on it's way out. Water quality is perfect and been having trouble keeping the sps colored up and keeping new sps alive. The bulb is also about 9months old and I wish I had but don't is a litemeter to measure my light through out my tank. The tank is 30" deep (it's a corner pentagon) and was looking for two opinions here. One is what bulb to change to and the second is how do I switch out the bulbs with killing what I have in the tank? Do I just decrease the number of hours exposed and then gradually raise it back up to 9hours aday photo period? What should I start off with for the a photo period,4hours? 5hours?
Mahalo for the input you folks are the best
Jack

 

[Chris L]

if you are a paid member the club actually has a light meter that it loans out. contact gina mcreeferson for info

 

[Jacksparrow]

Aloha, mahalo very much. I shall be contacting her very soon. Jack