Growth to RTN

[BluewaterLa]

Using a ''normal'' amount of carbon in a reef tank, about 1/4 to 1/2 of recommended for well over two decades now has shown no ill will toward fish or other critters in any of my systems and this would include Acropora.
Having explosive growth as you describe will indeed cause a decline in available nutrients / food source for the corals along with the tell tale sign of increased demand for carbonates as you have seen.
During such periods depending on your system and care provided it is possible to get the balance of Nutreints/ chemistry / lighting out of whack in a short period of time. This is the easiest way for me to explain this without trying to sound like a scientist.

In short if you have a large number of corals for the tank volume having a rapid good growth period and nothing else changes in the amount of fish poop and or supplemental feedings to keep nutrient levels somewhat stable you could have a period of running too clean and coupled with high powered lights of today can lead to issues.
I am not saying that you are doing anything wrong, what I am trying to convey in simple ways it that I have had this very issue on more than one tank I've cared for and always came down to the same set of issues with many corals having accelerated growth and nothing else changing.

Everyone has to Remember that achieving both great color and fast growth in stony corals Is a delicate balance of many parameters/ variables pertaining to the whole life support system. Usually trying to achieve both at the same time is keeping the tank on the edge of disaster.
It does seem with your nutrient levels and other posted parameters you posted that you have a great middle road approach to get both safely done without going extreme as some folks tend to do.
One thing that would help this out and help you pinpoint an issue would be to test every day for a solid month (if that is a good time frame for the problem) ensuring that you test Nitrate, Alk, cal levels along with other things going on such as water changes, feeding, light intensity and duration with keeping a written log with this information. Also detail some of the corals when doing well then the decline period.
Having record of this gives a map of events taking place within the tank and information for those days of good and bad.
It could be something simple like lack of Amino / fatty acids in the water from not enough fish waste when the corals are having explosive growth, saying basically they are using up / stripping the water of what they need to sustain such growth and thus causing their own decline unfortunately.
A remedy for this would be more fish OR adding supplemental amio acids in small quantities daily.

Even though you are keeping your nitrates at 10 ppm doesn't actually mean that enough essential nutrients are present for the corals health.
Nitrate is consumed by corals just like Phosphate in some quantity and these two are what we can test for and we use as a guideline for nutrients in our systems but it does not tell the whole story.
I do hope you get to the bottom of this issue and highly recommend keeping a detailed log with daily testing for a while as it has helped me constantly throughout my years of reefing.
Lastly I would put some thought into rapid depletion of needed nutrients / amino's for example or other trace elements being depleted during this rapid growth period leading to the tissue loss.

One other thing to think about is upsetting the ecosystem by constantly adding a few new corals on a regular basis weather just to replace what has died or collecting a few new ones as this can have negative affects on a reef tank in terms of stability as well from my experience.
Good luck and happy reefing
BluewaterLa/ Mike

 

[BluewaterLa]

I change 15 gallons of a 130 gallon system weekly religiously....right down to the same day and time each week lol. Have been doing that for a year and a half. The only thing I dose is 2-part and acropower once a week. I have adjusted lighting but it has been a ridiculously slow process.....only increasing intensity by 1% every two weeks (afraid to go any quicker since I have had these RTN issues over the past year). I am currently only sitting at maximum intensity of 57% using two Gen 3 Radion Pros over a 105 gallon tank.

I see that you posted that you dose 2 part and acropower once per week.
This would be a great starting point for you to start dosing your 2 part daily to avoid swings in DKH.
I was never able to keep the more demanding or delicate specimens of sps including Acropora when dosing once per week years ago, Even though I thought that the fluctuations were minimal and had no bearing on the success or failure with these corals. I was mistaken/ wrong about that and when I finally started to dose daily I achieved success finally. Then found I was having issues here and there with certain ones still then went to an auto doser spreading out the daily dose throughout the day and the level of stability achieved with a doser has lead to even better results.
Still testing on a regular basis is needed as equipment failure/ malfunction is going to happen at some point or conditions change in the reef that require more or less to be added.

I think that is what you meant when you state you dose 2 part and acropower once per week, that Both are only once per week right ?

 

[Waters]

I see that you posted that you dose 2 part and acropower once per week.
This would be a great starting point for you to start dosing your 2 part daily to avoid swings in DKH.
I was never able to keep the more demanding or delicate specimens of sps including Acropora when dosing once per week years ago, Even though I thought that the fluctuations were minimal and had no bearing on the success or failure with these corals. I was mistaken/ wrong about that and when I finally started to dose daily I achieved success finally. Then found I was having issues here and there with certain ones still then went to an auto doser spreading out the daily dose throughout the day and the level of stability achieved with a doser has lead to even better results.
Still testing on a regular basis is needed as equipment failure/ malfunction is going to happen at some point or conditions change in the reef that require more or less to be added.

I think that is what you meant when you state you dose 2 part and acropower once per week, that Both are only once per week right ?

Sorry, there was some miscommunication. The 2-part is dosed via Apex Dos, daily. The Acropower is dosed once a week.

 

[Waters]

Using a ''normal'' amount of carbon in a reef tank, about 1/4 to 1/2 of recommended for well over two decades now has shown no ill will toward fish or other critters in any of my systems and this would include Acropora.
Having explosive growth as you describe will indeed cause a decline in available nutrients / food source for the corals along with the tell tale sign of increased demand for carbonates as you have seen.
During such periods depending on your system and care provided it is possible to get the balance of Nutreints/ chemistry / lighting out of whack in a short period of time. This is the easiest way for me to explain this without trying to sound like a scientist.

In short if you have a large number of corals for the tank volume having a rapid good growth period and nothing else changes in the amount of fish poop and or supplemental feedings to keep nutrient levels somewhat stable you could have a period of running too clean and coupled with high powered lights of today can lead to issues.
I am not saying that you are doing anything wrong, what I am trying to convey in simple ways it that I have had this very issue on more than one tank I've cared for and always came down to the same set of issues with many corals having accelerated growth and nothing else changing.

Everyone has to Remember that achieving both great color and fast growth in stony corals Is a delicate balance of many parameters/ variables pertaining to the whole life support system. Usually trying to achieve both at the same time is keeping the tank on the edge of disaster.
It does seem with your nutrient levels and other posted parameters you posted that you have a great middle road approach to get both safely done without going extreme as some folks tend to do.
One thing that would help this out and help you pinpoint an issue would be to test every day for a solid month (if that is a good time frame for the problem) ensuring that you test Nitrate, Alk, cal levels along with other things going on such as water changes, feeding, light intensity and duration with keeping a written log with this information. Also detail some of the corals when doing well then the decline period.
Having record of this gives a map of events taking place within the tank and information for those days of good and bad.
It could be something simple like lack of Amino / fatty acids in the water from not enough fish waste when the corals are having explosive growth, saying basically they are using up / stripping the water of what they need to sustain such growth and thus causing their own decline unfortunately.
A remedy for this would be more fish OR adding supplemental amio acids in small quantities daily.

Even though you are keeping your nitrates at 10 ppm doesn't actually mean that enough essential nutrients are present for the corals health.
Nitrate is consumed by corals just like Phosphate in some quantity and these two are what we can test for and we use as a guideline for nutrients in our systems but it does not tell the whole story.
I do hope you get to the bottom of this issue and highly recommend keeping a detailed log with daily testing for a while as it has helped me constantly throughout my years of reefing.
Lastly I would put some thought into rapid depletion of needed nutrients / amino's for example or other trace elements being depleted during this rapid growth period leading to the tissue loss.

One other thing to think about is upsetting the ecosystem by constantly adding a few new corals on a regular basis weather just to replace what has died or collecting a few new ones as this can have negative affects on a reef tank in terms of stability as well from my experience.
Good luck and happy reefing
BluewaterLa/ Mike

Thanks for taking the time to type this all out ......what you are saying makes sense with the nutrients bottoming out due to the rapid growth...once the growth stops, the nutrients build back up and the cycle could potentially start all over again. I guess (like you stated) I need to figure out how to maintain those nutrient levels. Fortunately I do keep detailed logs of all testing and maintenance via Apex but I will admit I do not test anything daily except ALK. Your advice seems to make absolute sense though.

 

[McMullen]

I agree with @BluewaterLa

Rapid growth = rapid metabolic demand. Could be starving. None of the other suggestions make since for your situation, though they are likely more common problems.

 

[Big E]

The only thing that adds up to me from what I have read is pests, specifically acro flatworms.

Mainly because your other Sps along with LPS are fine.

I would suggest chipping off one of the strugging acros and really examine them............hit it good with a turkey baster, check for eggs ect.

Millis and tri colors are usually their favorites.

 

[DSC reef]

I agree with @BluewaterLa

Rapid growth = rapid metabolic demand. Could be starving. None of the other suggestions make since for your situation, though they are likely more common problems.

I wouldn't say that exactly. We're all trying to help here. A lot of the posts make sense since other corals are not being affected and it's only the acropora. It could be a little of everything from chemistry to pests.

 

[McMullen]

It could be a little of everything, but what is the likely hood of that? Extremely low given the OPs description of events and process of elimination. At some point you make a decision and say, okay I've checked for A and that's not it. Now B, no that's not it, etc.

I personally think @BluewaterLa nailed it. The other post really don't make since in this particular case. The OP has already been checking for the usual suspects.

 

[Waters]

It is possible that it could be a little of everything.....at this point I am heavily leaning towards some type of nutrient issue though. It makes sense based on how my issues come and go, almost following a calendar. If I have good growth for several weeks, I start watching and waiting for the first sign of RTN, which always comes. If it were pests (or any other water problem) I would think there wouldn't be growth at all, and the acro affected would always die. For example, when I first created this thread, I was seeing the first signs of RTN. Now, as it always happens, it has stopped and I am seeing good growth again on all coral. I guess the issue now is figuring out what nutrient is being depleted and trying to maintain that missing nutrient at all times. It doesn't appear to be any of the normal ones like Nitrates or Phosphates. That being said, there has been a ton of useful information in this thread which has caused me to rethink a lot of what I am doing.

 

[jda]

Low phosphate levels can promote rapid growth in anything that calcifies - specifically SPS and coralline. Are you using GFO that take the P way down, growth comes from low P environment, then P rises again before new GFO, coral stresses with higher P levels... all on a cycle?

I did not see P on your parameter list, but if you are doing anything to control it, I might suggest a Hannah 736 checker.

 

[Waters]

Low phosphate levels can promote rapid growth in anything that calcifies - specifically SPS and coralline. Are you using GFO that take the P way down, growth comes from low P environment, then P rises again before new GFO, coral stresses with higher P levels... all on a cycle?

I did not see P on your parameter list, but if you are doing anything to control it, I might suggest a Hannah 736 checker.

Yes, I do run Rowaphos and yes, I do have extremely low phosphates (sometimes registering 0 checked with the Hannah checker). I have never registered anything close to high levels though....I am shocked with I register any reading other than 0. I did check to see if my RTN events coincide with the changing of my carbon and GFO and it doesn't appear that they do (based on information provided and recorded using an Apex). Definately gives me something else to think about though. One easy test to determine if that is a possibility is to decrease the amount of time between my GFO changes. I might do that anyways with both my carbon and Rowaphos, just to eliminate any possible swings.

 

[saltyfilmfolks]

It could be a little of everything, but what is the likely hood of that

Quite high. If a coral is in poor health anything can tip the balance.
We humans would call it "sickly"

I wouldn't say that exactly. We're all trying to help here. A lot of the posts make sense since other corals are not being affected and it's only the acropora. It could be a little of everything from chemistry to pests.

I have an acropora problem in one tank. Started a couple months ago. Only some acros effected only some sps effected.

@Waters I've seen these before here and even on trtion tests , high nutints , low nutrients , high ligh, low light, there's just not an answer is seems.
I've got two tanks, virtually identical and one is having a problem. Mind boggling.

 

[ihavecrabs]

Do you dose daily or hourly? If it is daily, I'd recommend splitting it up a bit to favor less KH and pH swings.

Also, if you don't test at the same time each night, I would suspect that might also contribute to swings given that you only dose once daily (if I understood your dosing correctly).

GL!

 

[Waters]

Quite high. If a coral is in poor health anything can tip the balance.
We humans would call it "sickly"


I have an acropora problem in one tank. Started a couple months ago. Only some acros effected only some sps effected.

@Waters I've seen these before here and even on trtion tests , high nutints , low nutrients , high ligh, low light, there's just not an answer is seems.
I've got two tanks, virtually identical and one is having a problem. Mind boggling.

Thanks Salty....at least I know it just isn't me lol.

 

[Waters]

Do you dose daily or hourly? If it is daily, I'd recommend splitting it up a bit to favor less KH and pH swings.

Also, if you don't test at the same time each night, I would suspect that might also contribute to swings given that you only dose once daily (if I understood your dosing correctly).

GL!

The dosing is done hourly (sometimes even less than that) through the Apex Dos. I do have very little ALK or PH swings.....those are actually one of the more stable parameters in my reef. The only time I see a change in ALK is when the RTN starts, and the growth stops. Because of this, I now test ALK nightly so that I can adjust the dosing as needed, to counteract any swings.

 

[ihavecrabs]

The dosing is done hourly (sometimes even less than that) through the Apex Dos. I do have very little ALK or PH swings.....those are actually one of the more stable parameters in my reef. The only time I see a change in ALK is when the RTN starts, and the growth stops. Because of this, I now test ALK nightly so that I can adjust the dosing as needed, to counteract any swings.

Excellent!

 

[saltyfilmfolks]

I think we can safely rule out swings.

Fwiw. My happy acro sps clam tank is a non sumped 30g with an old tunze skimmer and aqua clear refugium and a jebao doser.

It should swing hard enough to hit a cat. I'll test the alk at some point this week.

 

[Waters]

I think we can safely rule out swings.

Fwiw. My happy acro sps clam tank is a non sumped 30g with an old tunze skimmer and aqua clear refugium and a jebao doser.

It should swing hard enough to hit a cat. I'll test the alk at some point this week.

That is the way tanks should be.......with my tank, if I walk by it too quick, SPS flesh seems to fall off. Maybe things are too stable lol.

 

[saltyfilmfolks]

That is the way tanks should be.......with my tank, if I walk by it too quick, SPS flesh seems to fall off. Maybe things are too stable lol.

Sps or acro?

 

[jda]

Yes, I do run Rowaphos and yes, I do have extremely low phosphates (sometimes registering 0 checked with the Hannah checker). I have never registered anything close to high levels though....I am shocked with I register any reading other than 0. I did check to see if my RTN events coincide with the changing of my carbon and GFO and it doesn't appear that they do (based on information provided and recorded using an Apex). Definately gives me something else to think about though. One easy test to determine if that is a possibility is to decrease the amount of time between my GFO changes. I might do that anyways with both my carbon and Rowaphos, just to eliminate any possible swings.

I think that you can eliminate Phosphate highs and lows as the cause. You might have to get up .5 or 1.0 or more to really slow down growth.

Having zero is no good. If you are using the 736 Hannah Low range checker, then I would try and keep between 2 and 5 in there. 2-3 is my target which is near what seawater is in RHF parameter papers. I might suggest that you cut back on the GFO so that you show some phosphates... low is not a problem, but zero can be.