Acropora help!

[BrokeReefer]

Hi everyone, I’ve had a frag of red dragon acropora in my tank for about 3 months now and seemed fine until tonight when I noticed some flesh missing. I’m reaching out for help because it’s my first acropora and I’m relatively new to the hobby. The tank is an all-in-one jbj 24gal nano and has been running for 1 1/2 years. Stocked with two clowns, one six line wrasse, and a cleaner shrimp. CUC are a few snails and a few crabs. I’ve been using Red Sea Coral Pro salt with 5 gal weekly w/c. I run a little purigen along with chemi-pure elite in the first intake chamber and the 2nd chamber I have chaeto growing on an opposite light schedule. Display lights are two AI Primes running at 50% power tuned to BRStv recommendations. Feeding is once a day of mysis and rod’s and once a week reef roids mixed with oyster feast.
Salinity 1.025
Temp.~ 79 deg
PH 8.0
Calcium 420
Alk 8.1
Po4 0.00 (Hanna checker)
No3 0 (API test kit)
Mag 1350
Here’s a few pictures. Any suggestions? Thanks in advance.


I also wanted to add, about two weeks ago I was a away from the tank for a couple days and accidentally left the doser off. When I returned alk dropped to about 5.5. Over the next 3 days I got it back up to ~8.0. Could I be just now seeing the effects of that? FYI I’m dosing tropic Marin carbocalcium-calcium and bio mag.

 

[Viking_Reefing]

The thing that stands out the most is that your nutrients seems to have bottomed out which is never good. Than in combination with an alk swing could potentially be the cause.

Try raising born N and P to detectable levels.

 

[Sweet Reef Corals]

Although I am not sure the pics are showing red dragons, what I am noticing is that your tank alk is 8.1 and you’re using RS Coral Pro. RSCP mixes to about 12dKh. My personal remedy would be for you to use a salt closer to your range.

 

[Osaurus]

I'd personally space out your water changes a bit more - 20% weekly is significant, especially when your phosphate and nitrate levels are already so low. Try aiming for 10% weekly or possibly every two weeks until you have detectable levels of NO3/PO4.

Your tank does look great though, so you're obviously doing a lot right.

 

[BrokeReefer]

So I just got home, and found a lot more tissue gone. Half of the frag is now completely white.

 

[drawman]

Unfortunately I doubt it will make it but sometimes a couple small spots hold on with stability. Doesn't look like there is an area to frag from the picture but you could try that if there is a branch leftover. I think as others have said maintaining detectable nutrients and using a lower dKH salt will help with stability in the future.

 

[BrokeReefer]

Thanks for everyone’s input. The coral completely bleached within 24 hours and unfortunately did not make it. Does anyone have any tips on how to raise nitrates and phosphates a bit. For the past year or so, I’ve always read 0 on phosphates on the Hanna checker. I have the regular checker(not the low range model). As far as nitrates, when I check with my Red Sea kit I’m usually around .25ppm. It’s always stayed pretty consistent regardless of how much I feed. The only thing I see with more food is more algae. Also the test readings I posted were after 3 weeks of no water changes.

 

[drawman]

Thanks for everyone’s input. The coral completely bleached within 24 hours and unfortunately did not make it. Does anyone have any tips on how to raise nitrates and phosphates a bit. For the past year or so, I’ve always read 0 on phosphates on the Hanna checker. I have the regular checker(not the low range model). As far as nitrates, when I check with my Red Sea kit I’m usually around .25ppm. It’s always stayed pretty consistent regardless of how much I feed. The only thing I see with more food is more algae. Also the test readings I posted were after 3 weeks of no water changes.

Get bottles of Nitrate and Phosphate from a company (like Brightwell) or make your own with Sodium Nitrate or Potassium Nitrate and Trisodium Phosphate. You may need to dose daily while numbers tank back to zero for a week or two just keep at it and keep measuring.