Coral growth question

[tylfly]

I am wondering if corals will expand less during a growth phase? I notice my corals will not fully expand from time to time.
Nitrites and ammonia are 0
Nitrates are 2.5
Cal 410
Alk 9.3
Sal 1.025
Temp holds between 79.8 and 80.4

 

[AlSimmons]

I've heard somebody say that before. By not expanding fully they're conserving energy so they can reproduce. I'm not sure if this would be true for your day to day growth though.

 

[Reef Bass]

I have not noticed that in my dozen or so years of reefing. Daily fluctuations in expansion are normal, such as when lights go on or off.

What kind of corals? If they're hard corals, low magnesium (which I don't see you mention) can cause grumpiness and a lack of polyp extension. Pests and polyp nipping by other tank inhabitants are other common causes of lack of polyp extension.

 

[ali1]

I notice corals stay reserved when phosphates are high. Start there

 

[jacksonpt]

I've heard somebody say that before. By not expanding fully they're conserving energy so they can reproduce. I'm not sure if this would be true for your day to day growth though.

This is more based on my logical thinking rather than any real knowledge/experience with long term coral growth, but...

If a coral isn't fully open, then it's not bringing in the most nutrients or absorbing the most light it could. So while it may be saving energy, it's also not getting/producing as much.

I've got to think that energy balance, in this case, is at best insignificant.

 

[tylfly]

I have noticed my gps stay closed up when they seem to take over more of the rock they are on, the long polyps leather seems to be the same every day. I also have a torch (that remains fairly consistent, but also retracts some from time to time), and 2 frogspawns. One is in the middle of the tank closer to the bottom, the other is the highest coral in the tank, but is more to the side with the return line not directly above it, but close to it. The frogs have fairly light flow on them (torch gets higher flow).
I have not worried about magnesium yet as my alk and calcium stay up fairly good. I have 80 gallons of total water and change 10 gallons a week. I feed fairly lightly, could it be a lack of feeding for the frogs?