acropora help

[justy]

Hi everyone.

I have been having issues with my acros stn,ing for the best part of two years.
All other sps doing ok good colour, pe and some growth.
My question is what would cause an acro to stn on the growth margins and then regrow a bit and then do the same again time after time on all the acros.
How stable is stable when it comes to kh I do have fluctuations of about .6 from time to time,is that enough of a swing to stress the acros.
I know there can be lots of reasons for stn but I have been keeping corals for a long time but for some reason that eludes me I can not grow acropora this time around.

Any suggestions would be gladly appreciated.

Thanks justin

 

[markalot]

It depends on the stability of other params in my opinion.

Acros don't like change. If everything is stable but KH then they might be able to handle it. If Phosphates, nitrates, salinity, other parameters are unstable or water changes are making KH quickly spike then it may be harming the corals.

Can you eliminate the spikes to see if they improve? IMO if they grow back then at times conditions are good, many people lose entire corals once they start to STN.

 

[justy]

Thanks Mark I am trying to nail the kh stability.
Lighting has certainly been an issue I have an it 2060 evergrow led light which I have struggled to find a setting that I am happy with I have recently added two t5 to supplement.
But constantly changing light settings I am sure does not help.

 

[markalot]

LED can be a pain if you don't have access to a PAR meter. It's probably a lot brighter than it looks, especially if you are running the blues brighter than the whites. I don't think that's the main coral issue but it may be adding to the stress as you suggested.

 

[bobssecrtsn]

What is your tank size? are you carbon dosing? any gfo? what inhabinets do you have? any fishes that nips on any of the corals? picture of the coral?

from what your thinking (alk burn) .6 swings arent that bad. you sshould look else where. have you done anything in the past month ? introduced anything to the tank?

 

[rickyb]

My first thought is a fish, invert or something else aggrevating the corals. I have never been lucky to save a coral due to STN. Direct water flow could also be a cause and have experience corals to grow again after correcting this.

 

[justy]

What is your tank size? are you carbon dosing? any gfo? what inhabinets do you have? any fishes that nips on any of the corals? picture of the coral?

from what your thinking (alk burn) .6 swings arent that bad. you sshould look else where. have you done anything in the past month ? introduced anything to the tank?

On this systesystem I'm trying to keep it simple.
I do not run gfo I do not carbon dose, I have a small bag of gac running passively in the sump.
I dose two part with a doser.
Parameters are
Kh 7.7
Ca 420
Po4 0.08
No3 3ppm
Sg 1.025
Mg 1480

Tanks size 28"24"24" 300ltr
It's definitely not the fish and it does not look like a pest of any sort.
The led unit does have a lot of the whites swapped out for more blues and I do run them at 100 %

 

[sharkboy99999]

Are you sure it's stn and not new growth (white tips)

 

[justy]

No definitely stn.

I have just changed my ro membrane and pre filters just to eliminate that side of it.

 

[justy]

Normal course of events is add a new acropora frag watch it base out over a month or two and then all of a sudden the base starts receding. During this time the corals in question retain great colour and pe.
Most times I lose the frag sometimes it tries to grow back.
Could it be to much blue light or fluctuating kh?
Corals are never affected on their tips, but rarely show new growth tips.

Any more ideas please I've been battling this issue for nearly two years,driving me nuts.
Wouldn't mind so much but my old tank, 10 years ago had great acro growth???

Many thanks justin

 

[EvMiBo]

seems like your alk should be fine/stable if you're dosing via 2part. that's probably not the issue.

I'm assuming your salinity is stable through ATO.

what are your temp swings like from day to night?

how long have you had the LED light? Do you remember if you've had issues since day 1?

What is the flow in the tank like? Perhaps direct flow as someone else had mentioned?

Since your nutrient export seems sufficient and as long as everything else in line that I mentioned above, I'd suspect lighting issues. I'd be tempted to put a 24" 8x24w ATI Sunpower on there.

 

[justy]

Hi yes all parameters are rock steady including Sg and temp.
I have loads of random flow.
Is it possible to have to many blue and uv leds and would my symptoms fit with to much blue and not enough white light.
And you are right if I had an ati I wouldn't hesitate putting it on.

Many thanks

 

[rickyb]

This is strange.
Can you list your fish and inverts you have in there? Have you noticed that the corals been affected are always in the same spot? That's if you have replace them and placed another in the same spot.

 

[justy]

Yes I have a yellow tang, red blotched perchlet , leopard wrasse and two thread thin cardinals and a cleaner shrimp and that's about it.
It is funny you ask about their position they are all generally on the top of the rock closest to the lights and I have remounted corals in the same position after one has died and the same thing happens.
Monties all doing great acans and pocies all fine just the acros that are high up on the rock work ????

 

[Bpb]

ill follow here as well

 

[rickyb]

What degree lenses do you have on the LED's? Maybe there is one specific LED that is affecting it.

 

[Bpb]

If you haven't already, remove the optics off of the red diodes. I still for the life of me can't understand why people want red diodes. I understand why builders use them, because of demand. People want "full spectrum". But the warm whites in those evergrows have plenty of broad spectrum reds it makes the narrow wave dedicated reds entirely unnecessary and in some cases harmful. I have multiple friends with these fixtures who all experience better results when either covering the Reds or removing the optics. One friend used scotch tape to cover them on his OR t247 unit. All the acropora directly under the Reds were bleaching badly before performing this fix. Probably NOT the source of your stn, but will definitely help to some degree

 

[justy]

Thanks for that I did cover them up for a short period a good while ago but only for a few days before I convinced myself I was being paranoid,but maybe there is something in it.
Will try again.

 

[justy]

Well got back home today and made two circular stickers and placed them over the red diodes.
What settings do most of your friends run there lights at do they have the blues at 100 %.
I reduced my blues from 100% down to 80%.
But maybe I should put them back to 100% and just change one thing at a time ie taking the reds out.
Thanks again for the ideas.

 

[Bpb]

If I'm not mistaken, the most recent person I bought coral from running them said he was at around 80% both channels, but he had his 12"+ off the water over a 180 gallon tank and was also running T5HO supplements. The tank was not overly bright but probably becasue the lights were so high up.