why is my coral turning brown?

[flintix]

My Zoanthids started turning brown last week. Tank's a 40-gallon with AI Prime lighting, running for about 8 months. Params are 0 ammonia, 0 nitrite, 10 nitrate, 8.2 pH, 1.025 salinity. Got a pair of Clowns and a Cleaner Shrimp in there. Been feeding Reef Roids twice a week. What's the deal?

[folius]

Sounds like your lighting might be off. How long you running the AI Prime each day? Also, what's your alk at? Brown usually means stress, could be light or params.

[infold]

Sounds like your lighting might be off. How long you running the AI Prime each day? Also, what's your alk at? Brown usually means stress, could be light or params.

Yep, alk's huge here. Mine did the same when my alk dropped to 6. Check that and maybe cut the light cycle by an hour. Mine bounced back in a week.

[Finleyt]

Yo, my Acros did this last month. Turned out my phosphates were sky high, like 0.15. You testing for PO4? Also, how old's your salt mix? Old salt can mess with trace elements.

[larkon8]

Brown coral's usually a sign of too much light or nutrient imbalance. What's your photoperiod? And are you running any carbon? Sometimes organics build up and cause this. I'd test phosphates like Finleyt said, and maybe dial back the Reef Roids to once a week.

[porkbun]

Could be bacterial too. Had a similar issue, added some microbacter7 and it cleared up. Also, double-check your magnesium levels. Low mag can make them look dull.

[flintix]

Thanks for the tips, gonna test alk and phosphates tonight. Lights are on for 10 hours, might cut it to 9. Forgot to mention I'm using Red Sea Coral Pro salt, mixed last week.

[folius]

10 hours is way too long for Zoas. Try 7-8 max. And yeah, Red Sea's good but double-check your mixing ratio. Overly salty water can stress them out.

[infold]

10 hours is way too long for Zoas. Try 7-8 max. And yeah, Red Sea's good but double-check your mixing ratio. Overly salty water can stress them out.

Second this. My Zoas bleach if I go over 8 hours. Also, how's your flow? Too little can let detritus settle on them.

[Finleyt]

If you're dosing anything, check that too. Had a buddy overdose iodine and his corals turned toasty. Random but worth mentioning.