Sps angry after reducing light.

[SamMule]

So, here is something interesting...
I removed 2 bulbs from my 6 bulb fixture to reduce PAR.
I expected to see corals "reaching" for light, but instead I am seeing some losing polyp extension and actually bleaching a bit.
I actually had to move my sunset montipora to a shaded section in the bottom to get PE and color back. This seems a little counterintuitive...
Can anyone explain this?

 

[Joedubyk]

What par were you getting vs now?

 

[SamMule]

I don't have a PAR meter, but I was having issues with corals getting too much light. Based on others measurements with similar setups, it had to be over 600 at the top.
Red Sea Max 250 with a ReefBrite actinic LED strip added to the front of the hood.
I understand removing 2 bulbs is quite a large change in lighting.(Should be ~30%, right?)
So, 400ish?

 

[Joedubyk]

You are straight guessing. That's your problem. Who knows? Rent a part meter or buy a seneye for 200 bucks. Its worth it!

 

[SamMule]

I've been thinking about getting the seneye for that. Numbers aside, I reduced light and now some corals are demanding less. The question is: why?

 

[Big E]

It is probably as spectrum issue, not par. You may have removed a spectrum the monti liked and moving to another area changed that for the better.

I would have kept all bulbs in and just raise the fixture or reduce the time period on your LED supplements.

 

[Waters]

In addition, any sudden change in lighting can cause issues if not done carefully....even if the change is beneficial in the long run.