Anyone have issues with new Phoenix MH Bulb?

[cfmx]

We purchased a new replacement 14K Phoenix 150w MH bulb for our solana.
Same exact bulb as what we had just replacing it since the old bulb was about year old.
Within days we noticed a difference w/ our corals. Acan was no longer puffy, zoas started melting away and SPS where turning brown.
I thought it had to be something else beside the bulb and started testing water. All looked good but a little low Ph 8.1 and Mag was low.
I slowing over course of couple weeks raised the pH and Mag but the corals still looked bad.
My only thought now was it had to be the bulb.
We put the old bulb back in last week and now the SPS colors are starting to color up again.
We have used Phoenix bulbs for 3 years on this tank w/ no issues so I'm not sure why now.
Any thoughts?? Or anyone else have similar issue?

[allsps40]

1 years IMO is a little long to go on a MH bulb. I replace mine every 9 months. Did you raise the light and/or decrease the light time to acclimate the corals to a new bulb?

[rtparty]

Sounds like an acclimation issue to me too. Whenever replacing bulbs you need to lower your photo period by a couple hours for at least a week and slowly bring it back up.