SPS question for all the seasoned reef keepers out there

Greatreefer · Dec 9, 2017

I'v e been in the hobby for a good part of 10 years now and have never really setup an SPS dominated reef tank before. So for my latest build I wanted to try my hand at trying to grow SPS corals. The corals that I then selected were montipora capricornis and monitopora digitata.
The corals have been in the tank for several months now and are all growing and thriving really well.
However, there are two that seem to be not doing well and have gone from vibrant colors down to a drab and almost colorless color.

In doing reasearch, Ive come across an several posts from people and a couple of articles talking about ULNs ( Ultra Low Nutrient systems and how some sps corals do not tolerate low levels of N03 and P04.
I'm wondering if the color change in the coral has any correlation between low nutrients levels of my system and the coloration of the corals?

What are your thoughts on this topic?

Below are the specs of my current system along with the current water parameters
for those who are curious.

System: REDSEA REEFER XL 425 (total 110 gallons)
Lighting:
2x radeon XR30W on for about 16 hrs a day

curculation:
2x maxspec gyres

return pump:
echtech vecra M1

Skimmer:
Reef octopus 150

fish load:
1x fox face
2x bangai cardnials
1x six line wrasse
1x cleaner shrimp

water parameters:
NO2: 2ppm
CA: 500ppm
Magnesium: 1500
alk: 8 DKH
P04: 0
Salinity: 1.027

DLHDesign · Dec 9, 2017

Where are the two "problem children" located in the tank? Have you tried moving them around (slowly, of course) to see if it's a light/shadow issue?

Greatreefer · Dec 9, 2017

I have moved then several times but in both cases polyps are fully extended just the total loss of color was visable. Plus i have other corals that are higher than those two and they are doing fine.

Greatreefer · Dec 9, 2017

Plus these frags are small and theres lots of grow out space. Nothing is shading them.

Mattrg02 · Dec 9, 2017

Bleached from too much light? You’ve got some powerful lightning and you run for 16hrs a day, which is a lot. I’d move them down and cut back on lighting. How are you measuring phosphate?

Greatreefer · Dec 9, 2017

Hana test kit.

brandon429 · Dec 9, 2017

I’ve never seen a 16 hour photoperiod mine is 9

Not that I have a prob with it, but that’s a standout. Better have nice target feeding for each coral all the time to sustain that type of photosystem workout. Surprised there isn’t more probs I think given time and no change in lighting, some will adapt to this and some won’t. It’s amazing you have no display tank algae problems

Post full tank shot if poss

Pics help more than params

Seminoles76 · Dec 9, 2017

If the rest of your coral seem to be colored up and thriving I wouldn't change a thing. I found it more harmful than not to start chasing things based off one or two corals not doing well when the rest of them are. Try moving it lower maybe or something to that effect but I wouldn't change any of the system main stays (parameters, lighting, etc.). I would only look at those if others started to decline as well.
Cheers

XNavyDiver · Dec 9, 2017

I see you've been in the hobby for 10 years. Is this tank also 10 years old?

Greatreefer · Dec 9, 2017

I will post picts here when the tank wakes up.

Greatreefer · Dec 9, 2017

I guess the big question: does n03 and po4 play a role in coral colors?

Mattrg02 · Dec 9, 2017

Greatreefer said:
I guess the big question: does n03 and po4 play a role in coral colors?

More or less. If your phosphate is truly 0 then you’ll need to get that up.

Greatreefer · Dec 9, 2017

XNavyDiver said:
I see you've been in the hobby for 10 years. Is this tank also 10 years old?

Sadly no.
This current system has only been setup a year.

Greatreefer · Dec 9, 2017

Mattrg02 said:
More or less. If your phosphate is truly 0 then you’ll need to get that up.

I kinda have a feeling that the teat kit ia faulty. I feed my fish 2x a day and the corals 1x a day. With that much food, it makes me wonder if the p04 and the no3 kits are accurate.

XNavyDiver · Dec 9, 2017

Greatreefer said:
Sadly no.
This current system has only been setup a year.

Was it set up with live rock or dry rock?

Greatreefer · Dec 9, 2017

XNavyDiver said:
Was it set up with live rock or dry rock?

Dry rock.

XNavyDiver · Dec 9, 2017

Greatreefer said:
Dry rock.

Bingo. Tanks started with dry rock struggle with sps for longer times than their live rock counterparts. Mine until just recently, wouldn't do it. Now, I've got a few "hardy" sps species and just started with a few tester frags of acropora. Their doing nicely so far, but have only been in the tank a few weeks, so the jury is still out as to how they will do in the long run.
How's your coralline algae growth?