HELP my transition to Radion Gen 4 (Corals Receding!)

[prior20]

Hello everyone! I have been dormant for a long time and everything has been going really well with my reef tank. I have a 150 tall that is on autopilot with BRS dosers and I do water changes every 2-3 weeks.

I recently switched from 250w 20k Radium MHs and wanted to try LEDs again. I attempted Radion Gen 2 awhile ago and did not have good success with them. I recently bought Gen 4s and now my SPS corals are losing color and starting to recede from the tips.

I started using the AB+ schedule at 40% maximum with a 4 week acclimation period starting at half of the 40%. Lights are sitting about 9 inches off the water, very close to what my MHs were ate.

Here are my parameters:
SG-1.025
KH-9
CA-420
PO4-0.6
Nitrates undetectable

I cut my lights off last night and am planning to adjust the schedule again. Does anyone have recommendations on how to better acclimate to the new light setup before I decide to hang my MHs back up?

 

[scuzy]

Could the intensity be too low and you're ramping up 4 weeks to Max 40.


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[prior20]

I was afraid I was hitting them with too much light but I started low because I had bleached my corals on my previous LED attempt. Could they recede due to low intensity?

 

[scuzy]

I just switched to g4 pros and I'm acclimating from 50% -85% on ab+ over 2 weeks. My corals took it well.


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[prior20]

Might try a higher intensity and see what happens. At first, they lost a little color and this week they began shedding near the tips.

 

[prior20]

I borrowed a PAR meter from my LFS. My SPS under the current max intensity of the schedule was mid 100s. Increasing to 100% intensity brought the PAR around my colonies to 280-330. I believe over the acclimation period of my lighting schedule, I may have starved out the zooxanthellae. Hoping to recover.

Would appreciate any tips on how to bring these colonies back to full health.

 

[mcgyvr]

Hang those MH back up and test..
I'd bet your PAR with those is far in excess of the mid 100s..
Good data to have if nothing else..

While mid 100's isn't horrible.. Its on the low end of what many SPS corals may need/be happy with..

 

[prior20]

I will do that tonight. Looking at my green slimer, the areas that are shadowed from the light a little bit was where it started to recede. I am taking that as a lack of light rather than too much light, which is what happened at my previous LED attempt.