What would cause slow growth, and even STN on acro, if all my other corals are fine?

[Reef Puncher]

If my water parameters were bad, wouldnt my other corals be affected? I have goniopora doing fine, montipora and stylo doing fine. All my tons of Euphyllia and torches doing fine. But my acros are struggling.

My parameters.

Alk has been shifting slightly lately as i trying to dial in the perfect amount of kalk with my AFR. It did bounce from 8.9 to 9.0 a couple times. is 0.1 considered swinging?
Calc- between 440-460
Mag- 1480
phosphates- range weekly depending on feeding coral food, between 0.05-0.1
nitrates- range from 7-11
salinity- 1.026
ph- ranges from 8.14 to 8.28

i tested my par and the acros are recieving about 320-480 depending on location.
i can not find any pests or worms.

 

[Pistondog]

Flow makes sps grow faster.

 

[Stevorino]

In my personal experience, Acros have been the most sensitive and hardest to keep corals.

Zoas, Euphyllia, Montis, Birdsnests, etc are all a walk in the park. I wouldn't hesitate to put any of those in a new tank, but I wouldn't put an acro in for a while.

The other observation I've had about acros in my tanks has been that they take a while to encrust and get settled in before they really start to take off. Whereas other corals seem to hit the ground running a bit faster.

The only 2 things in the OP that caught my attention were:

- I personally consider a .05 phosphate swing pretty big.... but I'm sure others have been successful with acros with that kind of swing.

- Par could be on the too high side depending on how long they've been under them and acclimated.

 

[Reef Puncher]

Flow makes sps grow faster.

i have an MP10 aimed slightly above my acros. set on reef crest random mode. can they handle direct in front of a MP10 if i moved it down like 6 inches? it would be aimed directly at them?

 

[Pistondog]

You dont mention how far away and the reef crest intensity.

 

[Dburr1014]

It did bounce from 8.9 to 9.0 a couple times. is 0.1 considered swinging?

No, that is solid.

i have an MP10 aimed slightly above my acros. set on reef crest random mode. can they handle direct in front of a MP10 if i moved it down like 6 inches? it would be aimed directly at them?

Don't hit them directly.

Only one powerhead?
MP10, small tank? You didn't mention the size.

 

[exnisstech]

I'm far from an expert. By struggling do you mean slow growth or STN / RTN? I started an acro tank February 2023 and had very little growth until after the one year mark. I've seen pics of tanks that people show colonies after a year but mine were almost stagnant for the first year before they started basing out then branching.
Mentioning flow since folks here are questioning yours. I have 2 mp10s and 2 Nero 5s in a 36x24x24" tank. I watch a Jason Fox video once and said he thought flow was more important than lighting.

 

[Reef Puncher]

No, that is solid.

Don't hit them directly.

Only one powerhead?
MP10, small tank? You didn't mention the size.

2 mp 10s in a 60. one on each side. and the powerhead actually moves quite a bit of water

 

[Reef Puncher]

I'm far from an expert. By struggling do you mean slow growth or STN / RTN? I started an acro tank February 2023 and had very little growth until after the one year mark. I've seen pics of tanks that people show colonies after a year but mine were almost stagnant for the first year before they started basing out then branching.
Mentioning flow since folks here are questioning yours. I have 2 mp10s and 2 Nero 5s in a 36x24x24" tank. I watch a Jason Fox video once and said he thought flow was more important than lighting.

so background. my tank is almost at the 1 year mark. i added acros about 3 months ago. they have not grown a single millimeter. no encrusting, no branch growth. now one of my acros is starting to STN, its getting white at the base. looks like its bleaching almost. i wonder if 400 par is too much for it? or maybe its getting too much flow or not enough flow? its hard to know how much flow for acros.

 

[Reef Puncher]

You dont mention how far away and the reef crest intensity.

um intensity is at about 40% if i remember.

 

[twentyleagues]

Flow could be the reason. I have had the same issue in my tank (cube=hard to get flow right) I added another power head and stuff is starting to look better already.

 

[Dburr1014]

so background. my tank is almost at the 1 year mark. i added acros about 3 months ago. they have not grown a single millimeter. no encrusting, no branch growth. now one of my acros is starting to STN, its getting white at the base. looks like its bleaching almost. i wonder if 400 par is too much for it? or maybe its getting too much flow or not enough flow? its hard to know how much flow for acros.

Is that xenia?
You do run carbon, correct?
Mixed tanks are hard. Softies trying to kill off the hards.

I truely think Flow is tied to lighting. The more light, the more flow you need. Do you have another ph to pop in there?

 

[Reef Puncher]

Is that xenia?
You do run carbon, correct?
Mixed tanks are hard. Softies trying to kill off the hards.

I truely think Flow is tied to lighting. The more light, the more flow you need. Do you have another ph to pop in there?

yep xenia on the back wall. its not touching the acro tho. i might have a spare powerhead. but my eupyhllia are getting a ton of flow as is. the torches are swaying all over the place.

 

[Dburr1014]

yep xenia on the back wall. its not touching the acro tho. i might have a spare powerhead. but my eupyhllia are getting a ton of flow as is. the torches are swaying all over the place.

I put my lps near ledges to protect them from flow.

 

[UMALUM]

Flow is a stimulate and some acros like more than others. Unfortunately that's something only you can observe and make the necessary adjustments. For me especially with a dormant acro polyp extension is key followed by color. If your not seeing any extension day or night then likely the coral is shutting down and will likely starve. Sometimes in younger systems nitrate and phosphate just simply isn't enough and you might need to supplement a little something to get them to respond. Not sure how your replacing trace but LPS and zoas can be iodine pigs.

 

[Reef Puncher]

Flow is a stimulate and some acros like more than others. Unfortunately that's something only you can observe and make the necessary adjustments. For me especially with a dormant acro polyp extension is key followed by color. If your not seeing any extension day or night then likely the coral is shutting down and will likely starve. Sometimes in younger systems nitrate and phosphate just simply isn't enough and you might need to supplement a little something to get them to respond. Not sure how your replacing trace but LPS and zoas can be iodine pigs.

i been doing ICP's one a month until i figure out a balance of my trace. my iodine was low, your right. and my iron was low due to the chaeto. i have been supplementing recently. im starting to think its my light or flow. might be my light is too strong. its sitting around 440 ish near the acro thats dying

 

[Pistondog]

2 mp 10s in a 60. one on each side. and the powerhead actually moves quite a bit of water

Not enough flow. I have an mp10 and another phead in a 20 gallon, mp10 runs reef crest, max 75%, too noisy after that.
I removed all xenia a year ago as i believe they throw chemicals into the water. Running carbon helps.

 

[Reef Puncher]

Not enough flow. I have an mp10 and another phead in a 20 gallon, mp10 runs reef crest, max 75%, too noisy after that.
I removed all xenia a year ago as i believe they throw chemicals into the water. Running carbon helps.

so both my powerheads are on 40% i can try cranking them up.

 

[UMALUM]

i been doing ICP's one a month until i figure out a balance of my trace. my iodine was low, your right. and my iron was low due to the chaeto. i have been supplementing recently. im starting to think its my light or flow. might be my light is too strong. its sitting around 440 ish near the acro thats dying

I think your nutrients and alk can support 440 no problem. Your numbers aren't that far off mine and I'm sure there's spots in my system getting well over 600. A little advice that probably won't help now but will in the future is not every frag is gonna make it and that doesn't mean there's something wrong with your system. There's so many variables in this hobby that can't be measured or controlled that losing sleep or trying to tweak your system to fit the needs of a couple upset corals is a lose lose. Look for a supplement low in potassium iodine that you can work in your schedule and maybe some vitalizer to offer an alternative for nutrition. Flow or lack there of is more likely to lead to a bacterial issue well before SDR happens.

 

[jk1knight]

I personally started feeding my corals amino acids and reef chili and reef roids. Anecdotally, it seems to have accelerated growth. Maybe I am just buying the sales pitch? It makes sense to me from a biology standpoint. Definitely remove the Xenia. Carbon seems to help my tank also by reducing coral warfare chemistry. The problem you have is that it takes quite some time to see a change in SPS growth. You can tweak flow. You can tweak lighting. You can tweak tank chemistry. You are not going to notice any difference for quite some time. In the end, I can almost never tell what really made the difference. As you know, water changes, flow and light are all critical, but every tank is different. I have been successful in the past by putting 2-3 frags at different heights in the tank and see what thrives and what does not. I then try to rescue the underperforming frags. Best of luck…