How to treat RTN in SPS corals?

LPS, SPS and all coral chat
florapine
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Joined: Thu Oct 10, 2024 4:35 pm

How to treat RTN in SPS corals?

Post by florapine »

My Acropora started showing RTN overnight. Parameters are stable, 8.1 dKH, 420 Ca, 1350 Mg, 0.03 PO4, 5 NO3. Running a Red Sea Reefer 350 with Radion XR15s. Any quick fixes before it spreads?
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Kalixar
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Joined: Sat Jul 06, 2024 10:02 am

Re: How to treat RTN in SPS corals?

Post by Kalixar »

Cut the affected branches at least an inch above the necrosis. Dip the frags in Revive or CoralRx, then glue them to fresh plugs. Check flow, sometimes dead spots trigger RTN. What's your alk swing like?
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medic_1
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Joined: Thu Oct 10, 2024 2:47 am

Re: How to treat RTN in SPS corals?

Post by medic_1 »

florapine wrote: Wed May 28, 2025 6:15 am My Acropora started showing RTN overnight. Parameters are stable, 8.1 dKH, 420 Ca, 1350 Mg, 0.03 PO4, 5 NO3. Running a Red Sea Reefer 350 with Radion XR15s. Any quick fixes before it spreads?
Had the same issue last month. Bumped my water changes to 20% weekly and added extra carbon. Stopped the spread in my tank.
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Elpenz
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Re: How to treat RTN in SPS corals?

Post by Elpenz »

yo, alk swings are sketchy. my monti got wrecked cuz i was lazy with dosing. u gotta keep it tight, no more than 0.5 dkh fluctuation. test daily till it chills.
anglermatic
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Joined: Sun Sep 11, 2022 4:29 am

Re: How to treat RTN in SPS corals?

Post by anglermatic »

Sorry to hear about your Acropora. I've found that reducing light intensity by 20% for a few days helps stressed corals. Also, double-check your salinity with a calibrated refractometer. Small things add up.
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reef_lord9
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Joined: Wed Oct 09, 2024 9:46 pm

Re: How to treat RTN in SPS corals?

Post by reef_lord9 »

dunno bout all that chem stuff but my lfs told me to toss in some microbacter7. worked for my birdsnest. might just be luck tho.
Wildzone
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Re: How to treat RTN in SPS corals?

Post by Wildzone »

RTN is often bacterial. Try a broad-spectrum antibiotic like erythromycin in a quarantine tank. Dose at 250mg per 10 gallons for 5 days. Monitor closely.
florapine
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Joined: Thu Oct 10, 2024 4:35 pm

Re: How to treat RTN in SPS corals?

Post by florapine »

Thanks for the tips. Cut the bad bits and dipped like Kalixar said. Alk was steady at 8.1 for weeks, but I'll test twice daily now. Gonna reduce lights too.
duneshape
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Joined: Thu Oct 10, 2024 7:04 pm

Re: How to treat RTN in SPS corals?

Post by duneshape »

reef_lord9 wrote: Wed May 28, 2025 1:15 pm dunno bout all that chem stuff but my lfs told me to toss in some microbacter7. worked for my birdsnest. might just be luck tho.
microbacter is legit, but it's more for biofilm. won't stop rtn if your alk's whack.
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fortuna_4
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Joined: Thu Oct 10, 2024 3:49 am

Re: How to treat RTN in SPS corals?

Post by fortuna_4 »

my tank's too new for sps but following this thread. good luck op.
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