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I've been tweaking my LED settings for weeks but my Acropora still looks bleached. Running a 75-gallon tank with Radion XR15s, 10 hours total, peak at 80% intensity. Par readings are around 350 at mid-level. Any suggestions?

Yo, 80% might be too much for Acros if they're bleaching. Try dialing it back to 60% and see if they chill. Also, what's your alk sitting at? If it's swinging, that'll mess with them more than light.

ladren wrote: ↑Sat Jul 26, 2025 7:28 pm Yo, 80% might be too much for Acros if they're bleaching. Try dialing it back to 60% and see if they chill. Also, what's your alk sitting at? If it's swinging, that'll mess with them more than light.

Agreed. Alk stability is key. I run my XR15s at 65% peak with a 12-hour ramp, and my Acros are thriving. What's your nutrient load like? High phosphates can also cause issues.

I'd check the spectrum too. Too much blue can stress them out. Maybe tweak the channels to lean more white or violet. My tank's similar size, and I run a 14K look with 70% blue, 50% white.

Honestly, 350 PAR is solid for Acros. Maybe it's not the light but something else. How often are you doing water changes? And what salt mix? Some brands are sketchy with trace elements.

I had the same issue until I adjusted my photoperiod. Try shortening the peak intensity duration to 4 hours instead of the full 10. My corals perked up after I made that change. Also, what's your flow like? Too little can cause stress.

Boldy wrote: ↑Sat Jul 26, 2025 10:37 pm Honestly, 350 PAR is solid for Acros. Maybe it's not the light but something else. How often are you doing water changes? And what salt mix? Some brands are sketchy with trace elements.

Yep, second this. I've seen tanks crash from bad salt. I use Red Sea Blue Bucket, 20% changes weekly. Never had issues.

Thanks for the tips, everyone. I'll try reducing intensity to 60% and check my alk. Using Tropic Marin Pro salt, 15% changes biweekly. Flow is two MP40s at 70%. Appreciate the help!

I'm new to this, but could temperature swings be a factor? My tank stays at 78°F, and my corals seem happy. Just a thought.

I've heard some folks say UV can help with bleaching. Not sure if it's true, but might be worth looking into.