One acro and one stylapora receeding

Treefer32 · Dec 4, 2021

I have a stylopora that's been receeding now for months. It's tops are all still bushy, but the inside of its base is all white. And slowly branches have been dying off. I thought it was just it's too crowded and dying off. But, not I have my best acro that's quadrupled in size for almost a year and 90% of its branches are still growing and have great polyp extension. However two branches at the center of the coral are pale or turning white. I don't know if it's from shadowing.. e.g. the other branches are too crowded and killing the inner branches through lack of light. Or is it a water quality issue where the branches are starting to die from the inside out. I have several cuttings of this coral that are easily 3-4 months old on my frag rack and they're continuing to grow and showing no signs of distress.

I did just change my year old T5 bulbs about 3 weeks ago. But I run AI Hydra 52s with my T5 aquatic life fixture, so, I don't know that replacing the bulbs would make that much of a difference. I tested my water and alk is 10.2 (about where it stays daily). Phosphates are managed at .07 ppm. (They've been there for around the last 6 months. They were higher before that.) Nitrates have drifted from 19 ( tested 2 weeks ago) to 27 tonight with hanna nitrate tester. I'm wondering if nitrates are drifting to the intolerable range. I've increased vodka dosing this week, but after raising it 2ml per day more as of Monday of this week, Nitrates aren't coming down. I'm wondering if vodka dosing has reached it's limits. With phosphates that low and nitrates that high. I run an algae turf scrubber as well and seems to be growing algae a bit slower than before, Where the screen was completely full within 3 days and now it's taking closer to 4 days to be full. Seems like something is inhibiting my nitrate export mechanisms.

I think I'm going to have to do a water change to get the nitrates cut down and then monitor to see if they continue rising.

T-J · Dec 5, 2021

You said both colonies were slowly losing tissue from the inside, which leads me to believe it's a shading issue. Especially since other things are growing without any signs of tissue loss.
I have one acro in particular that will not grow tissue on the underside, but continues to grow like a weed and have crazy PE where the light is hitting it.
As far as nitrates, you can add some bottled bacteria to lower them naturally. I don't think 27 is "crazy high". Many people like to be around that 10-15 range.

Treefer32 · Dec 5, 2021

Thanks! I agree, I have other SPS and acros growing rapidly. My all of my hammers are doing great. I had just gotten a couple months ago a orange and gold hammer. The gold hammer has 2 new heads and a tiny 3rd head coming in already. I've got a tiny green gonipora, it's so tiny it's barely visible, but it's the goni that could. It's grown from 1 tiny polyp to 3. So, I don't suspect water quality if everything else is doing well. I'm trying to reposition the rocks slightly. But, It's ultimately crowding itself. A good problem, in my opinion.

sculpin01 · Dec 6, 2021

Nitrate elevation may be a factor and should be reduced (I like to do lots of water changes myself but pick your own poison). However, I’ve also heard bacterial infection hypothesized for tissue loss in mature colonies. A 30 minute Amoxicillin dip might be worth a shot.

Although dearth of flow can contribute, I seriously doubt it’s as big an issue as is made out after watching some of the new reef cams. The corals shown on the “ReefOS” cam in Mo’orea are in what appears to be pretty torpid conditions, yet they are perfectly healthy.

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Treefer32 · Dec 6, 2021

Well, I think I found the culprit. I noticed the polyps all oddly shaped and odd looking at the center of the colony. I noticed my return nozzle pointing straight at the branch that was dying. I tested the flow with my hand and the stream was dead center on the branch that was having issues. So, I redirected the return nozzle. I'm guessing it'll be fine now. I may have tested the limits of flow on an acropora. Ha, they don't like being blasted in the face!