Poor Polyp Extension

[Snowsrfr]

Recently I've noticed poor polyp extension on some of my SPS that normally have great PE. Oddly, some still have fine polyp extension. Some with poor PE are green mili, ATL Shades of Fall, ORA Red Planet, sunset monti, German Green polyp, German blue polyp, etc...While I still have good PE on hynophora (sp?), birdnest, red digitata, Idaho Grape, etc...

Checked all my levels yesterday and the only thing I could find is Alk a little high (yet still in range) and Ca a little low (yet still in range).

SG 1.024
P04 0
Amm 0
Nitrate 0
Alk 12
Ca 350
pH 8.1-8.2
Mag 1400

Which do you believe to have more impact on PE, Ca or Alk, or could both being slightly out of whack be the problem?

Anything else I should be checking for due to a sudden decrease in PE?

 

[Reef Bass]

Alk of 12 would be my immediate concern. I suggest dropping that slowly (like no more than a point a day). While calcium of 350 isn't an immediate death bringer, in the long run, it will not allow the coral to achieve its full potential.

You didn't mention your temp or whether it fluctuates much over a day? Any toxin producing lps corals in there? Any little critters (flatworms, redbugs) on the frags with poor polyp extension?

 

[Snowsrfr]

I'll work on slowly bringing the alk down then.

No pests that I have seen, but I will double check tonight.

My heater is controlled by an APEX so temp only fluxes by no more than a degree over 24 hours.

The only LPS I have in my tank are 2 chalices, a pipe organ colony, and bleeding apple scolymia.

 

[Logzor]

Get a flashlight and monitor these corals in the middle of the night. If they have good PE at night then fish might be nipping at these particular corals during the day. If this is the case you may need to supplement more food/nori for these fish.

As mentioned look for pests such as redbugs and AEFW. It is not uncommon for corals to have good polyp extension until they are overburdened with pests. Perhaps these corals are just now showing visual cues that they are in distress.

Double check your salinity with a freshly calibrated refractometer. I have found that high salinity will cause lack of pe on some corals.

 

[Snowsrfr]

I'm going to recalibrate my refractometer and re-check salinity tonite.

Will also check polyps tonite, after lights go out.

 

[ratsckor]

Just wanted to jump in and say that my red plant has done the same thing in the last few days. I did my normal water change and added my normal elements. The only thing i know has happened is that the water has dropped in temp and that is the only thing that is different with my system in the last few months.

 

[Snowsrfr]

I recalibrated the refractometer and verified I had a SG of 1.024, turned down the Ca reactor a bit to try to bring the Alk down and dosed with Kent's Liquid Calcium to try and brind up the Ca a bit.

Double checked and had no pests on any of the affected corals, but didn't get a chance to check night time polyp extension. Gonna have the wife check before the lights come on this morning.

Also, added a bag of carbon to the return section of the pump, just in case the few little LPS I do have are putting off any chemicals.

 

[Snowsrfr]

Think I may have found the culprit!

Called my wife from work this morning to have her check and see if the affected corals had any polyp extension with the lights out. She told me no, but there was a green crab curled up on one of the colonies. Looks like my emerald crab has been climbing on the corals around his lair, or at least I hope that is what it is. When I think about it, all the corals that are closed up are in the vicinity of where the emerald crab hangs out, while the lower colonies/frags away from his home are unaffected.

He has been banished to the refugium in my sump, and I hope to see some polyp extension once again.