Slow growth, little polyp extension, but good color

Ghost25

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I have a 20 gallon mixed reef 10 months old. Over the last 6 months I have lost some SPS, mostly new additions, it seems if they survive the first couple of weeks they survive long term but they don't grow very quickly. Currently I have Anacropora, stylophora, pocillopora, birdsnest, and two Acropora. Most of the additions that died were Montipora or Acropora.

I realized I wasn't testing like I should and bought some tests. Found my nitrate and phosphate were both elevated. Started more water changes, GFO, and carbon dosing.

Current parameters:

Alk: 8.3
Phosphate 0.98
Nitrate: ~20
Calcium 425
Temp 79F
Salinity: 1.026

I have a skimmer, good flow (MP40 + return pump), an AI Prime and Kessil A80.

Coral colors are good, but polyp extension always disappears compared to the frags when I get them. The main issue is slow growth, I have heard high phosphates inhibit growth. Does it seem likely that high phosphates are the main reason for slow growth or something else?


Happy Zoas

1228211914.jpg


This Slimeball has been very hardy and has grown noticeably but still quite slow, the hammer is happy, the monti has encrusted a bit but that's it in a couple months

1228211914a.jpg


The stylo is one of the oldest corals in the tank and has grown a bit, but the stylo and acro both had much more polyp extension when I got them.

1228211915.jpg
 

Lavey29

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It's either lights, flow or nutrients. If the first 2 are ok then you probably have identified one of your problem areas with high phosphates. Nitrates slightly elevated also. Have you done an ICP to check trace elements? That ciukd also be hindering you.
 
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Ghost25

Ghost25

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It's either lights, flow or nutrients. If the first 2 are ok then you probably have identified one of your problem areas with high phosphates. Nitrates slightly elevated also. Have you done an ICP to check trace elements? That ciukd also be hindering you.
Flow I think is plenty, I recently turned the MP40 up a bit and sand is now piling up in some areas so I might even turn it down a bit.

I'm not worried I have too little light, bit possibly too much? I mean it seems unlikely but I have heard of photoinhibition. Not sure an A80 and AI prime over a 20 gallon is gonna get there though.

No ICP test.
 

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Do you have a way to test pH?


Also if that is correct that is very, very high for phosphate

What settings are the lights running and at what height?
 
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Ghost25

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Spare time

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Yeah figured phosphate was the issue. Though there are some people that run them that high or higher with success, I realize they are outliers.

https://www.reef2reef.com/threads/rich-ross-home-tank-guess-the-phosphate.296635/#post-3626579
https://www.reef2reef.com/threads/1ppm-phosphate.846852/#post-9186851

A80 intensity is ~80% and 80% towards blue, runs from 9:30AM to 10PM. AI prim from about 10AM to 10PM with 3hr ramp up and down.

I can probably test pH at work.
Do you know the intensity of the prime and the mounting height of both?

Also is the tank a 20 long or 20 high?
 

Greg P

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PO4 is NOT high. Many tanks thrive at up to 0.1
IMHO, back off the carbon dosing and GFO. Stop trying to use so many things all at once to solve it.

Go back to when you know things were doing well, and then start SLOWLY changing things ONE thing at a time
 
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Ghost25

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PO4 is NOT high. Many tanks thrive at up to 0.1
IMHO, back off the carbon dosing and GFO. Stop trying to use so many things all at once to solve it.

Go back to when you know things were doing well, and then start SLOWLY changing things ONE thing at a time

Maybe you misread, my phosphate is 0.98ppm which is nearly 10x that (I used Hanna ULR phosphate checker and had to dilute my sample 1:2.) I'm not married to the carbon dosing but I have a relatively large bioload and I'm skimming 24/7. It's an all-in-one (Waterbox Cube 20), so I don't have a place for an algae scrubber. If not carbon dosing what do you recommend? Seachem Matrix or similar?

It's not that things started going bad, it's that hardy corals survive but more difficult corals RTN within a week or two of adding them.

Did a bit more research and I think high phosphate may be causing low polyp extension and RTN of Acros as well.
 

Greg P

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When I wrote up to 0.1 PO4, I meant Phosphate, not Phosphorus. Phosphorus is written as P

Maybe you misread, my phosphate is 0.98ppm which is nearly 10x that
I did not misread your post, and your level is not 10x that if you properly posted your results.
If you're using a Phosphate test it's as you posted.
If you're using a Phosphorus test, such as a Hanna ULR, then you'd be wanting to convert your results.
And using that test kit, you'd not be seeing test results with below decimal readings.

Try it without diluting your sample.

I own both kits and use both regularly.
 
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Ghost25

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When I wrote up to 0.1 PO4, I meant Phosphate, not Phosphorus. Phosphorus is written as P


I did not misread your post, and your level is not 10x that if you properly posted your results.
If you're using a Phosphate test it's as you posted.
If you're using a Phosphorus test, such as a Hanna ULR, then you'd be wanting to convert your results.
And using that test kit, you'd not be seeing test results with below decimal readings.

Try it without diluting your sample.

I own both kits and use both regularly.

I'm not sure where the miscommunication is. I also meant phosphate, and have only said phosphate in my posts. My test kit tests for phosphate (PO4): https://www.bulkreefsupply.com/phos...rimeter-hi774-hanna-checker-marine-water.html

It is the HI774 not HI736. The HI774 claims to test 0.00 to 0.90ppm phosphate.


When I said my level is 10x that was in response to your comment:

PO4 is NOT high. Many tanks thrive at up to 0.1

Because my PO4 = 0.98 and you said tanks thrive up to 0.1 and 0.98 is ~10x of that level. I am unable to test without diluting because the meter maxes out at 0.90ppm, so when I test my sample undiluted it is out of range.
 

Greg P

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Because my PO4 = 0.98 and you said tanks thrive up to 0.1 and 0.98 is ~10x of that level. I am unable to test without diluting because the meter maxes out at 0.90ppm, so when I test my sample undiluted it is out of range.
Ah, I see

Not to worry, you are still well within a good range for keeping most corals.
NO3 and PO4 are acceptable (currently for 2020) within 5-20ppm and 0.03-0.10
I did not see what Magnesium testing you have done.
 
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Ghost25

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Confused ...
What is your test result ?
It's still 0.98ppm phosphate.

I'll spell it out again. I have a Hanna model HI774. The HI774 tests phosphate (the anionic molecule composed of one phosphorus atom and four oxygens.) It measures this compound in a range of 0.00 to 0.90ppm.

You seem to think I have the Hanna model HI736 which tests phosphorus alone, even though I said I didn't have that. Then you posted a picture that says how to convert the phosphorous reading from the HI736 to phosphate. But I don't need that because: I DON'T HAVE THE HI736, I HAVE THE HI774 WHICH REPORTS PHOSPHATES NOT PHOSPHORUS.
 

damsels are not mean

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Turn the lights down and see what happens. Most likely too much light. Don't worry about them not getting enough. You won't kill them. Too little will brown the corals out long before it causes them to not grow or even die. Too much? That'll absolutely slow the growth and damage them in some cases. Is there a difference in these symptoms at different heights? Corals do best with growth just above 100 PAR. Some might have a sweet spot somewhere above that, but 200+ all corals start to slow down.

Phosphates? Nitrates? I don't think so. I'm pretty sure elevated nutrients like that cause more growth not less. The reason those nutrients can slow growth is because it makes the symbiodinium inside the corals more competitive for carbon, but this is only an issue with low alk. In your tank, I don't think that is an issue. It also would only affect corals that need to build a skeleton.

Admittedly, your phosphate seems kind of high compared to a lot of the coral gurus, but Richard Ross gave a talk at MACNA where he showed insane growth and also phosphate testing results above 1 and even up to 2 IIRC. Some of the other really awesome tanks where designer sticks grow like weeds have much higher than the "approved" 0.05 level.
 

Charlie’s Frags

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Have you checked your par. I have a prime 16 on a 12” cube 6g frag holding tank and you’d be shocked how low par those are. My settings are much higher than yours and only get 200 par at the 6” mark of my tank.
 

JCOLE

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Do you know what your daily pH is? If so, what is the lowest and at what time and what is your highest at what time? Low pH will stunt your growth and cause other issues with overall health. Maybe something as simple as getting your pH up.

I say this because it just happened to me. I have an Acro dominate tank and over the last 5 months things were just not growing at all. My pH probe read around 8.4 so it never dawned on me. I decided to recalibrate my probe to make sure and it was 7.8ish after recalibration!!! I plumbed my skimmer intake outside for fresh air and put my kalkwasser back online. Now my pH is between 8-8.3 daily and I can see new growth daily on almost all my pieces.

Also my No3 and Po4 were very elevated. Once I adjusted the pH and the corals started growing then the nutrients came down because the corals were consuming them.

pH might not be your problem but it's a must to check for if having growth issues. If you don't have a controller then grab one of the Pinpoint pH monitors. They are less than $100 and worth it to test your daily pH.
 
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Ghost25

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Do you know what your daily pH is? If so, what is the lowest and at what time and what is your highest at what time? Low pH will stunt your growth and cause other issues with overall health. Maybe something as simple as getting your pH up.

I say this because it just happened to me. I have an Acro dominate tank and over the last 5 months things were just not growing at all. My pH probe read around 8.4 so it never dawned on me. I decided to recalibrate my probe to make sure and it was 7.8ish after recalibration!!! I plumbed my skimmer intake outside for fresh air and put my kalkwasser back online. Now my pH is between 8-8.3 daily and I can see new growth daily on almost all my pieces.

Also my No3 and Po4 were very elevated. Once I adjusted the pH and the corals started growing then the nutrients came down because the corals were consuming them.

pH might not be your problem but it's a must to check for if having growth issues. If you don't have a controller then grab one of the Pinpoint pH monitors. They are less than $100 and worth it to test your daily pH.
That makes sense, the tank is in my bedroom which has been fairly closed up because it's winter. It's 8" from the window so it shouldn't be too hard to run an airline.

I was running Kalk in the ATO but stopped recently, I'll restart but using less Kalk.
 
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