Acropora polyps stunted?

[ZachR32]

I've had my a pair of nano tanks running for a while now. The sps originally came from a 40 breeder where I was dealing with the same issues I have now. Nitrates steady between 5-10 ppm, phosphates always around .03. Calcium 450 mag 1400 and alk around 7-8.

I have good growth on montipora, birdsnest and stylos but for the life of me my acropora have no growth. They've all been in the same condition for about 6 months now. Polyps only extend about halfway with no new growth showing and no tissue recession. Flow is pretty strong and the lighting is a viparspectra mounted about 10 inches off the water at 40% blue and 15% white.

Any one have any ideas on what I could be missing? I have no trouble growing acropora under the same lighting in a 125 g. Many thanks for any suggestions

 

[vpoiu1263]

Just increase your light power, more white light .
I think you will get result soon about 1 month.

 

[fabutahoun]

Can You Measure the PAR before increase the light intensity, also how much flow do you have?

 

[najer]

A pic would help, I don't now that light but it looks like quite low settings.

 

[ZachR32]

I don't have access to a par meter and cannot afford one. When in the 40 there were three jebao pp4s on full blast, currently in the 14 gallon there is one jebao at about 65%. I'm pretty sure flow is good, always try to keep it turbulent with no direct blasting

 

[ZachR32]

Here's the best I could get before heading off to work. There is some growth on the green planet in, but all the polyps seem to be only halfway extending

 

[fabutahoun]

Try to increase the white a little by 5% only and see the coral response.
There are other 2 possibilities that I can think of for stunned polyps, either you have a fish like some kind of angel or butterfly nipping at the polyps , or the worst case scenario Acropora Eating Flatworm. you can dip one of the corals and check for worms and eggs.

 

[ZachR32]

Yea I'm thinking you might be right about the light. I don't think I have any AEFW because I haven't seen any tissue recession but I'll dip and look anyways. Also the only fish are a yellow chronic and sailfin blenny. I suppose the blenny could be a culprit but I haven't caught him in the act yet

 

[mitch91175]

Big question is polyp extension the only way you can determine a corals health? What if the coral is just fine in your tank but just don't want to reach out until it's well established. I ask because you may not have any issues but could maybe begin to introduce some feeling that polyp extension is the gauge.

 

[ZachR32]

Definitely not, I've seen plenty of tanks with no PE and solid growth. My concern was if there was any connection between stunted PE and something I was missing. I haven't seen any growing tips or spreading bases, and I suppose to be more i accurate I should have measured them when I first introduced

Big question is polyp extension the only way you can determine a corals health? What if the coral is just fine in your tank but just don't want to reach out until it's well established. I ask because you may not have any issues but could maybe begin to introduce some feeling that polyp extension is the gauge.

 

[Charlie’s Frags]

What is your nutrient export method? Are you carbon dosing or using gfo? How high are your lights mounted? You said you have strong flow, but it could be too much if you have sand in small tanks.

 

[Auto-pilot]

I have a vipraspectra light and my acropora frags are growing slowly. Whites don't help much. I run mine at 60% blues 15% white. I would slowly ramp up blue to get it higher and see what happens

 

[Dburr1014]

I'm no expert but it looks like to me they are encrusting at the base.
After they get a good base they should grow upward. And of coarse, don't fiddle with them. [emoji16]