Acan is sunken in

[BigJohnny]

So I would try moving the acan around to different spots to see if it opens back up and if that does not work then I would go ahead and change the lights back.

Agree with shep. You have to leave it in each spot for a few days though

 

[abecker]

Sounds good, i'm going to give it a few more days where it is, and then I will try some other places.

 

[TheEngineer]

It probably isn't the light, but rule 1 of troubleshooting is, "Undo whatever you did right before the problem occurred and see if the problem goes away"

At the very least, don't do more than one thing at a time. Try the lights for a few days, see if it helps. If not, try moving it to a new spot, leave it for a few days. Etc... Do whatever steps you think most appropriate.

 

[reefhobby]

What size tank

 

[abecker]

Standard 125

 

[pk_hk]

Its the diatoms, which can be toxic. You could elevate the colony until the algae subsides. Lighting should be fine.

 

[BigJohnny]

Its the diatoms, which can be toxic. You could elevate the colony until the algae subsides. Lighting should be fine.

That is probably the least likely of all possible causes and unrealistic. 99.9999% of diatoms are not toxic.

 

[pk_hk]

That is probably the least likely of all possible causes and unrealistic. 99.9999% of diatoms are not toxic.

To be clear: consider the diatoms (which can be toxic) and the implications. Dinos and cyano (also potentially toxic) can take hold under these conditions. Also, 0 phosphates with the presence of diatoms means the acans are being robbed of the nutrients they enjoy.

 

[BigJohnny]

To be clear: consider the diatoms (which can be toxic) and the implications. Dinos and cyano (also potentially toxic) can take hold under these conditions. Also, 0 phosphates with the presence of diatoms means the acans are being robbed of the nutrients they enjoy.

I am considering, and dismissing the concern. Diatoms are rarely toxic in reef aquaria, and cyano must actually be on the coral to effect it in my experience. Diatoms feed primarily on silicate, not phosphate. Regardless, i have .02 ppm phosphate and my acans flourish. My guess is that OP is using standard hobby grade phosphate test kit, which can not even detect .02 ppm phosphate accurately. I would say a lack of testable phosphate and the presence of diatoms are the least likely causes of the corals recession. That's all I'm saying. You can't exactly find a lot of anecdotes or studies on toxic diatoms in reef aquaria, can you?

 

[abecker]

Yeah I have an API test kit for phosphates, and if it reads 0 I still make the assumption that there are some there. I feed a little heavy so I can't assume that a 0 reading is actually 0.

 

[BigJohnny]

Yeah I have an API test kit for phosphates, and if it reads 0 I still make the assumption that there are some there. I feed a little heavy so I can't assume that a 0 reading is actually 0.

Yea, even if they were accurate to that level, the ability of the average human eyes to interpret the results correctly increases the margin for error.

Don't get me wrong, toxic diatoms (literally never heard of this in reef aquaria) and lack of phosphate are possible causes, but high nitrate/phosphate is more likely, even when you test them low (and that's only because your using API). The most likely causes are light/flow/irritation by livestock

 

[BigJohnny]

Yea, even if they were accurate to that level, the ability of the average human eyes to interpret the results correctly increases the margin for error.

Don't get me wrong, toxic diatoms (literally never heard of this in reef aquaria) and lack of phosphate are possible causes, but high nitrate/phosphate is more likely, even when you test them low (and that's only because your using API). The most likely causes are light/flow/irritation by livestock

I do recommend you get better test kits however, just as a general recommendation. I personally have experienced the innacuracy and inconsistency of API test kits. Salifert is cheap tried and true. Hanna are my favorite but more expensive. I also use red sea Nitrate pro

 

[pk_hk]

I am considering, and dismissing the concern. Diatoms are rarely toxic in reef aquaria, and cyano must actually be on the coral to effect it in my experience. Diatoms feed primarily on silicate, not phosphate. Regardless, i have .02 ppm phosphate and my acans flourish. My guess is that OP is using standard hobby grade phosphate test kit, which can not even detect .02 ppm phosphate accurately. I would say a lack of testable phosphate and the presence of diatoms are the least likely causes of the corals recession. That's all I'm saying. You can't exactly find a lot of anecdotes or studies on toxic diatoms in reef aquaria, can you?

Diatoms can bleach poryphyra. I was rhetorically redirecting the attention away from the suggestions to readjust lighting or as you suggested, or playing musical chairs. This would only stress the acan further. On behalf of the OP, I wouldn't panic, the acan is most likely not in immediate danger but I would look to restoring a healthy sandbed—and most importantly what that would take. I'd test TDS as the diatoms are fond of silicate and most likely consuming a fair amount nitrate and phosphate. The problem is not the accuracy of the of test kits, or even so much the results (nothing surprising there) but the sources and utilization of the nutrients in the tank. As long as the diatoms aren't flourishing, target feeding would get you back on the way to a fat and happy acan. I've never seen acan fond of diatoms. FWIW, diatoms do stress and kill corals. Recent papers I've read suggest its the results from the coral's need to produce mucus in defense and an ultimate smothering that occurs.

 

[BigJohnny]

Diatoms can bleach poryphyra. I was rhetorically redirecting the attention away from the suggestions to readjust lighting or as you suggested, or playing musical chairs. This would only stress the acan further. On behalf of the OP, I wouldn't panic, the acan is most likely not in immediate danger but I would look to restoring a healthy sandbed—and most importantly what that would take. I'd test TDS as the diatoms are fond of silicate and most likely consuming a fair amount nitrate and phosphate. The problem is not the accuracy of the of test kits, or even so much the results (nothing surprising there) but the sources and utilization of the nutrients in the tank. As long as the diatoms aren't flourishing, target feeding would get you back on the way to a fat and happy acan. I've never seen acan fond of diatoms. FWIW, diatoms do stress and kill corals. Recent papers I've read suggest its the results from the coral's need to produce mucus in defense and an ultimate smothering that occurs.

The diatoms are not on the corals so there is no smothering and no relation to the study your talking about. This diatom idea has zero traction.

However OP, if your not feeding your acans once a week then yes that could be a factor. They do require supplemental feeding.

 

[pk_hk]

The diatoms are not on the corals so there is no smothering and no relation to the study your talking about. This diatom idea has zero traction.

However OP, if your not feeding your acans once a week then yes that could be a factor. They do require supplemental feeding.

That's the point but you're on the wrong side of it. Ever stop to wonder why the diatoms are doing so well on the sand bed but having greater difficulty with the acan? Or I guess they're just happily sharing real estate just like everybody else on the reef?

OP, 0 TDS.

 

[BigJohnny]

That's the point but you're on the wrong side of it.

I have no idea what this means. My point was the diatoms are not on the coral so they aren't affecting it. Pretty straight forward.

Ever stop to wonder why the diatoms are doing so well on the sand bed but having greater difficulty with the acan? Or I guess they're just happily sharing real estate just like everybody else on the reef? OP, 0 TDS

First of all, no one said "the diatoms are doing so well". He said the brown spots in the picture are of diatoms. They aren't even covering the surrounding area in the photo so I would argue they actually aren't doing so well.

Even if they were doing fantastic, it has zero impact on the coral. I have 27 sps corals in my tank as well as 7 acan colonies and diatoms on my rocks. Why are their diatoms? Because I have a relatively new tank and the silicate has not been depleted from the rock yet.

My rodi water is 0 tds. Silicate has no negative impact on corals. Mollusks sponges and diatoms benefit from it. There is absolutely 0 empirical evidence that silicate, or the presence of silicate, has a negative impact on corals. So to say that there is a connection between a struggling acan (not necessarily struggling just receded) and diatoms flourishing, is incorrect. Provide evidence of otherwise or stop giving bad advice. You can do more harm then good and also waste people's time and money when you don't know what your talking about and act like you do.


Unless the diatoms are growing on the coral, they are not an issue

 

[pk_hk]

You've not understood a single thing I've said and have no right to challenge my experience which spans decades.

 

[BigJohnny]

You've not understood a single thing I've said and have no right to challenge my experience which spans decades.

I've said all I need to say to help the OP. I have no desire to discuss anything further with you.

Thanks

 

[abecker]

So I let it go without changing anything over the past week and it has started to look better and more puffed up. One thing I noticed is as my lights transition to all blue before lights out is when it will look a little sunken, but then I will check on it in the morning before the lights come on and when I first get home from work and everything is looking more normal.