lighting acclimation

[props]

just wondering if you guys have had problems with acclimating a coral properly to a new lighting..
i think its one of the main cause of losing a few sps of mine becuase i didn't acclimate them properly =o(
lost 4 differ acros within a week
1 acro i lost when i swapped my lighting setup from 175 to 250
after a day of having the new lighting setup the acro deterioriated in a 3 hour span
1 cap took a couple of days and the other 3 acro after a week.. =o(
trying to fid a reason on why i lost them =o(
wonder if its the recent removal of my dsb as well
i notice a 10ppm peak of ammonia right after i removed the dsb n reaquascaped the tank. then the nitrate spiked up to 15ppm after a couple of days . prolly help the stress on the tank
tank param.
ammonia -0
nitrite -0
nitrate -5ppm
ph. -7.9-8.2
alk -11dkh
ca -went from 420 to 380 during the dsb removal prolly due to
a 30% water change
haven't tested silica or phosphate