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My Acropora frags have been in the tank for about three weeks now, but they're not showing any color. Water params are good, 0 ammonia, 0 nitrite, 5 nitrate, 8.2 pH, 420 calcium, 1300 magnesium. Running Radion XR15s at 60% intensity for 8 hours. Any ideas what's missing?

Yo, sounds like your lighting might be the issue. Acros need that sweet spot of PAR, around 250-350. You gotta ramp it up slowly though, or they'll bleach. Also, check your alk stability. If it's bouncing around, they'll stay dull.

goaliepro wrote: ↑Thu May 01, 2025 4:21 am Yo, sounds like your lighting might be the issue. Acros need that sweet spot of PAR, around 250-350. You gotta ramp it up slowly though, or they'll bleach. Also, check your alk stability. If it's bouncing around, they'll stay dull.

Agreed. Alk swings are a killer. What's your alkalinity sitting at? And how often are you testing?

I've had the same problem before. Turns out my tank was too clean. Acros need some nitrates and phosphates to color up. Try feeding a bit more or cutting back on water changes for a bit. Worked for me!

What's your flow like? Acros need strong, random flow to thrive. If they're just sitting in a dead zone, they won't color up no matter what you do with the lights or params.

Honestly, three weeks isn't that long. Sometimes they just take a minute to settle in. Mine looked like crap for a month before they finally started popping. Patience, my dude.

Are you dosing anything? Amino acids and trace elements can help with color. I started dosing Red Sea Colors and saw a big difference in about two weeks.

phillis79 wrote: ↑Thu May 01, 2025 7:23 am I've had the same problem before. Turns out my tank was too clean. Acros need some nitrates and phosphates to color up. Try feeding a bit more or cutting back on water changes for a bit. Worked for me!

This is solid advice. I was running my nitrates at zero for ages, and my Acros were blah. Upped the feeding, and bam, colors came back.

What salt mix are you using? Some brands are low on trace elements. I switched to Tropic Marin Pro and noticed better coloration across the board.

Thanks for all the suggestions, everyone. I'll start by tweaking the lights and checking alk more frequently. Appreciate the help!