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nph

Duncan not really extending despite growing another head

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nph

I have a bio cube 28 with refugium with Chaeto, phosguard and chemipure in the back.

I have Star Poliyps, Ricordia, 2 Blastos, Candy Canes, Torch, Akans and a few rock flower anemones. All look really great except the Duncan.

It is kind of mid aquarium and has medium to low flow.

 

Alkalinity is a little low, no matter how I try I never get it higher than 7-8. PH around 8.1

Really low phosphate and almost NI/NA.

 

Temp is 77. Light is on 7 hours and at a decent low intensity to keep algae in check.

 

What am I missing to make my Duncan a bit more happy?

 

Thanks

 

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seabass
7 hours ago, nph said:

Alkalinity is a little low, no matter how I try I never get it higher than 7-8...  Really low phosphate and almost NI/NA.

Why are you using Phosguard when phosphate is really low?  And by really low, what is the actual value, and which test kit are you using to determine that?  Also, what is the actual level of nitrate, and which test kit are you using?

 

Similarly, we need to know a lot more about alkalinity.  What salt mix do you use (what was the initial level)?  What are you using to try to raise alkalinity?  What is your tank's magnesium level?  And also, what is the level of calcium?

 

My initial thought, reading the title, with a struggling LPS coral was alkalinity.  Which was reaffirmed by your post.  However, the post also points out a lack of nutrients, with multiple nutrient reducing methods being used.

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nph

So I just checked my water at my local LFS. 

Phosphate less than 0.1

Nitrite 0

Ammonia 0

Nitrate 0.1

Alkalinity 9

PH 8.1

Calcium 380 (need to dose a bit here)

 

I had a phosguard in there since I recently had some hair algae and from what I can tell it is gone now.

unfortunately so is the cheat... 

 

My LFS suggested I move the Duncan down from the brightest spot where it is now and that might help. What do you think?

Currently it is in the highest location close to the center.

i see the tentacles but quite short.

Or could there be another reason it doesn't really open up with extended tentacles?

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seabass

Less than 0.1 ppm phosphate could mean anything between 0.09 and 0.00; so I'm still not sure what exactly less than 0.1 ppm means.  Some people want phosphate to be 0.10 ppm, while others might feel that's high and would be more comfortable with a target of 0.03 ppm.  However, less than that could potentially cause problems for other photosynthetic organisms (I.e. corals).

 

Some people would consider 0.1 ppm nitrate low.  But depending on what your phosphate level is, it might be acceptable.  However, with phosphate below 0.03 ppm, that could be a problem.  Low nutrient levels can pose a problem for corals, especially if they are not being fed.  Not all corals should be fed, but LPS corals usually benefit from a small meaty meal (like a mysis) once or twice a week.

 

I'm still very unsure about alkalinity.  While an alkalinity of 9 dKH is fine (many would say spot on), you previously mentioned having trouble getting it above 7 or 8 dKH.  So I'm still not sure what you were using to try to raise it, or what level your salt mixes to.

 

The low calcium number now also has me wondering about magnesium.  As low magnesium will cause additions of alkalinity to force calcium out of suspension (and vice versa).

 

5 hours ago, nph said:

My LFS suggested I move the Duncan down from the brightest spot where it is now and that might help. What do you think?  Currently it is in the highest location close to the center.  i see the tentacles but quite short.  Or could there be another reason it doesn't really open up with extended tentacles?

We might benefit from a picture, to really see what it looks like.  I'm sceptical about the suggestion that too much light is the problem.  I'm even starting to wonder if there is a problem.

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nph

I moved it yesterday and I already see a small improvement compared to before.

Will start photo this weekend. 

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Saultman

I have 2 Duncan’s under med to high flow , med light that are doing great 6 new heads each in the 2 months . I also fed them quite a bit mysis and lps pellets 

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SaltyGallon

Not withstanding the uncertainty regarding your alk (you say it's low, but then up at 9?) I'd say just feed it more. Duncans love reef roids and pellets once they're settled and well fed they really take off. With the only Duncan I ever kept, the individual heads got much larger before it thought about throwing out babies.

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Grimes

My duncan seems to stay closed if the flow is even moderate. It likes nutrients p around 0.03 - 0.06 and N around 10

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