Zoas Lost Their Stem

[chem368]

I'm not sure what is going on with my Zoas. As you can see in the attached picture I have two colonies that just have the polops. They open up, but are smaller in size than when they had a stem/trunk (not sure what that part is called).

The continue to multiply and spread which I like, but am confused why they have shrunk down like this. I have two other colonies that look great and have not had the same effect.

Zoas are located at the bottom of the tank in a low-med. flow area. Have tried a few spot low in the tank with same results.

Tank is 66 Gal with 18 Gal sump with Vertex Omega 130 Skimmer and an MP40 for flow (flow fluctuates through the day via APEX controller). I dose Kalk via ATO and does 2 BRS 2 part as well. LED Lights are controlled through the day starting at 7:00am ramping up to 70% for a couple hrs and ramping back down by 8:00pm when the 1 blue channel is left on at 1% for moon light. I also run GFO and Carbon.

Water Parameters:
Salinity = 1.025
Temp = 78 - 79.5
Ph = 8.25 - 8.35
Nitrates < 5 ppm
Phos < 0.03 ppm
Cal = 420
Alk = 10.5
Mg = 1350

All checked via Red Sea Reef Pro kits - and verified at my LFS.

Thoughts? What am I missing? Would love for these to grow a little more vertical to fill out...

 

[dragonfly1972]

Mine extend their stems when they are looking for more light. I would suggest lowering them in your tank a bit and see if that changes them.
Oh darn...just reread that you had them low

 

[chem368]

I've read that about when they are to high. Since I can't go lower, and don't want to reduce my intensity due to SPS in the tank, maybe shortening how long they are on for?

13 hrs is kind of long, but I always figured since so much of lat was at a lower percentage output I was still good...

 

[dragonfly1972]

I'm no expert on lighting, but I do know what works on my tank.
Are your whites on for that 13 hours? Or does that include ramping up and down?
My lights start ramping up at 12 and down by 10. Whites on full for 7 of those hours.
I have a mixed reef. I would be more than happy to share my lighting schedule details if you wanted.

 

[chem368]

Thanks, I would be curious to see your lighting schedule. I will dig mine up when I get home today and post it along with my LED layout. I wonder if my lighting is causing problems. I might try moving the zoas to a semi shaded area and see what happens... I am reluctant to reduce my light intensity for my SPS (in fact I might still have to ramp it up), but shortening the day might help.

 

[Ryannn]

Do you run your skimmer constantly? I noticed once I got a skimmer and had it running 100% of the time, my Zoas starting losing their mat and pulling in. I started only skimming during the 'night' period, and my Zoas rebounded in about a week. I believe Zoas like water with a little more particulate matter in it.

I would start with adjusting your lights, though, since you have SPS.

 

[650-IS350]

Z's and P's usually elongate their stems to get more light.

I don't see any issue with yours. IF they're staying closed, melting or fungus issues then i'll be worried. But if they're continue to multiply, colors remain or get better then there's no issue.