SPS Polyp Extension Question

[gman2]

I have a 180 reef that has been up for over 3 years now. I started with softs and LPS and now have over the past couple years moved to sps with over 25 species now. The tank is lit with 2 400wt 20k HQI and 2 250wt 10k bulbs.

Several of my sps dont seem to have their polyps extend during the day. Some of them will have full extension in the center of the coral but not on the outside edges. Others have full extension while others have no extension in the day. It really didnt bother me to much until today. I traded several frags to my local store and with in 15 minutes ones that I could not get extesion with the lights on extended perfect in their tank with no acclimation. Some of the frags that I have aquired extended when I bought them, but not in my tank.

Any ideas??

my ph is 8.2-8.4 according to my neptune and tested with kit and is in same range.

Calcium is around 500
Alk is 9.6-10dkh
ph is 0
ammonia 0
nitrate/nitrite 0
Mag around 1500

All tested with salifert kits

I use a calcium reactor if that helps

I use ro/di water from a spectrapure unit

All the corals grow fine.

I am also thinking of changing my lighting to a 3-250wt hqi gieseman unit to save on the electricity.

Thanks for any input

Tony

 

[Len]

I've found I can induce greater polyp extension doing one of three things (or a combination of them):
1. Increase feeding schedule.
2. Reduce light levels.
3. Reduce dissolved oxygen levels.

For obvious reasons, I wouldn't recommend the latter two. If your corals are doing well, don't worry about polyp extension.

 

[gman2]

Thanks for the reply Leonard.

A couple quick questions.

What, how much and how often do you feed your tank? It looks awesome!!!

I dont really want to tone done the light, thats why I was thinking of the 250wt DE HQI. Any thoughts.

I really dont know how to reduce disslolved oxygen levels.
I use a Euroreef cs8-3 and it really doesnt pull out that much. I have it adjusted so that the riser literally is pullled all the way up and just barely sits on the o-ring seal.

I do have an ORP probe but I have not replaced/calibrated in a loooong time. It reads 310 but I cant trust that

Thanks Tony

 

[Anonymous]

hi.
Just want to say that I have some corals in very aweful shape, but the polyps still extend well. So just as Leo says, don't be too concern about this.

 

[Len]

Thanks, gman.

I feed my tank once to twice daily, mostly thawed out Ocean Nutrition Prime Reef (too lazy to make my own nowadays). I'll feed live brine in selcon as well as chopped krill occassionally, and I use DT and Bioplankton sporadically.

The 250 watts will definitely lessen overall radiation (assuming you're using a good reflector on your 400's right now), but again, I wouldn't opt for this course of action if your corals are doing well. Polyp extension is nice, but is definitely not a direct indication of health.