Polyps "reaching"....

[E.intheC]

When a zoanthid or polyp extends toward the surface, usually IME it's due to a low light condition. I don't think that's the case here though.

Currently in my tank most of my zoanthids are reaching toward the light, no matter where they're placed. (Two exceptions.. Red People Eaters and a very small yellow zoanthid).

My tank:

-Drilled 40 breeder set up for about 6 months or so
-250 watt Radium and PC actinic supplemental lighting.
-SRO 1000int skimmer.
-Good flow (return plus 2x Tunze 6025's pointed at each other so it's somewhat random)
-ATO system w/ 2 part
-Carbon Rx w/ GFO + Carbon changed montly.
-10% weekly ater change w/ RO/DI water

MH is about 12-14 inches above the water in a canopy. It's brand new (about 1 week old). I thought it may be due to an old bulb, but nothing has changed.

My testing hasn't revealed anything obvious:

-Zero nitrites/ammonia
-Undetectable Nitrates (I don't believe the test kit though)
-pH 8
-I can't remember what mag was (think it was 1200... I'll have to check my notes and post back)
-kh was a bit low for about 1 week at 6 but usually it's higher and w/in normal range. (I don't think this is the issue b/c they've been 'reaching' longer than a month or so).
-I don't have a hanna meter so I can't get a reliable phosphate reading (I don't trust the test kits).

All above using either Salifert or API...

No nipping or predators that I can see. My other corals (even some SPS) are doing fine. Not thriving with terrific growth, but not doing poorly IMO.

Any ideas? :idea: Thanks..

 

[kichimark]

How long have they been doing this? Is it a long stretch? What kind of flow are they in?

 

[E.intheC]

They've been like this for at least a month or so. I think they're in good flow areas. They seem to be doing it regardless however. As for length... Probably 1/2 inch stalks or so.

 

[jasonrp104]

Mine do the same thing under a 4 bulb T5. I'm sure light is the case sometimes but I figure if an acro is doing fine at the same height, it isn't an issue of light. My reds are the only ones that don't reach also. Reaching for food..maybe?

 

[E.intheC]

Could be reaching for food. I have never really fed zoos before and don't think its necessary in my tank hecause of the slightly elevated nutrients.

I wonder if its too much flow for them...

 

[Friday Night]

If it was to much flow they would be closed and stubby.