Corals bleaching and dying

[NLReefer]

Over the past month or so i’ve noticed my corals slowly start to bleach and die. It started with one head of my hammer coral, followed by another and another. It has since moved onto a branching green acro, my acan and a Favia. Once I noticed the hammer coral I checked every parameter I could. My system typically runs on the lower end as a mostly softie tank but alkalinity dipped to 5.9dKh, Cal at 325 and mag at 1440. Salinity was at 1.025 and temp at 75. Since then I have slowly increased the Alk back up and currently at 7.3 and calcium to 375. Unfortunately I haven’t seen any improvement in the Sps or LPS. Softies are still doing great tho. Wondering what everyones thoughts are as to the cause and how best to correct. I’ve also dimmed the lights to acclimation mode just in case.

 

[Dipan Desai]

What are your nitrates and Phostphates at? Also do you know par your hitting your corals with?

 

[NLReefer]

Nitrates are reading 0 and same with phosphate using an API test tho so it could be off a little. No idea of the par. Using a Kessil AP700 on a 60 gal long (48x12x 24 deep)

 

[MERKEY]

Zero N and P is no good...get some in there slowly. Do you have fish?

How old is your tank?

Alk and cal are low for that much mag and balancing those out will help also.

 

[Dipan Desai]

I would start with getting your nitrates and Phosphates up. Get your nitrates to 5-10 ppm and phosphates around .05. Your corals are probably starving. You should have plenty of light with the AP700.

 

[fcmatt]

How long is slowly getting alk up?