Thoughts on SPS polyp extension..

[StirCrazy]

polyp extention during the day is not a normal thing. I only had extension at night with all my corals, but for some reason people seam to like it. my theory is that if there extending there looking for food as the polyps are there food catching tools, but who knows, I could be out to lunch also... but from reading I did years and years ago no extension during the day was normal as they are feeding off the light, at night when there is no light or at times when the light isn't enough they will extend to both catch food and increase the surface area exposed to light.

Steve

[fishytime]

wild sps dont extend their polyps during the day due to diurnal predators...... nothing to do with available light or food.....I noticed a huge increase in PE when I started with phyto/zoo plankton feeding.....

[Haloreef]

I run three 400 watt halides over my 6' tank, believe me there is no light shortage. I think the polyps are extended during the daylight due to a lack of predators. Some seem to extend even more during lights out though!
Keith.

[Aquattro]

Keith, I run the same light, no polyps. Corals are all doing great, just curious why the polyps stopped coming out.

[StirCrazy]

Originally Posted by Haloreef

Some seem to extend even more during lights out though!
Keith.

thats what I would get, some extension during the day, at night it was way more.

Steve

[Jason McK]

It is my understanding that PE is a result of the coral sensing a level of available nutrient in the water. Like for example a Sun Coral and our ability to train it to open. A lot of fish feeding will trigger PE of all corals.
I don't believe sand storms would cause a lack of PE as most wild corals live in very turbulent areas with waves crashing directly on top of them.
It's my belief Potassium could be a trigger that tricks the coral to believe food is available. I also am a believer that Potassium is an important in a reef, but be very careful as over dosing will kill fish

J

[Bblinks]

I had a potassium shortfall on my tank, I use redsea pro kit to test for potassium. My reading was just under 360, I have since bumped it up to 430 ish with zeovit k balance. I have found it useful looking at the new polyp extension on several of colonies of sps which had no extension before and with brighter blue coloration. I do run pellets on the system, I strongly believe while running a probiotic system potassium gets striped out of the system way too fast, one must replenish it with supplements to ensure sufficient levels are met. Ofcourse with most supplements I don't like to dose anything I can't test.

On a side note. I found feeding also aid polyp extension as it is the reason why there is polyps in the first place.

I am interested in the grounding probe. I guess it's time to stick the good old multimeter in the water and see if there is any stray voltage.

Keep us posted on the progress.

[daniella3d]

My sps have full polyp extension 24/7. The only time they retract is when I touch them or when I do water change and they are exposed to air.

I guess my tank must not be normal.

Originally Posted by StirCrazy

polyp extention during the day is not a normal thing. I only had extension at night with all my corals, but for some reason people seam to like it. my theory is that if there extending there looking for food as the polyps are there food catching tools, but who knows, I could be out to lunch also... but from reading I did years and years ago no extension during the day was normal as they are feeding off the light, at night when there is no light or at times when the light isn't enough they will extend to both catch food and increase the surface area exposed to light.

Steve

[Aquattro]

Originally Posted by daniella3d

I guess my tank must not be normal.

No, it seems sort of normal to be out, depends on the tank. Lots of great tanks have full PE, and lots don't.

For me, adding K has produced a bit more PE, but nothing substantial. I do have perhaps 12 colonies that have full PE, but another 80 that don't. Not sure why.
I added some brine shrimp today to see if that provoked more response, nope. I feed mysis daily, no change. I've just modified my zeo dosing, I may have been adding too much, so perhaps the corals aren't hungry. I have nothing picking at them, so it's not predation.
Levels are all really good and stable. alk is a bit high for a zeo system, so perhaps that affects it, since the water change that seemed to set this off did raise my alk substantially. I'm trying to get it back down to 7dKh and see if that changes anything.
Again, not sure if PE during the day is a good thing or a bad thing, I do have typical PE at night, corals are colored great, and growing well, so I really don't have a problem, but they do look prettier when extended.

[StirCrazy]

Originally Posted by daniella3d

My sps have full polyp extension 24/7. The only time they retract is when I touch them or when I do water change and they are exposed to air.

I guess my tank must not be normal.

nope 12 years ago we rarley saw huge polyp extension during the day. for the last 22 years I have been diving hawaii, and other places same thing little or no polyp extension during the day lots at night. so to me that says that is normal.

a few papers I have read years ago linked extension to suspension feeding, others I have read link it to increasing surface area for light adsorption, so who realy knows......

I never worried about it much myself.. heath and color were what was important, never was extension during the day ever an indacator of health so I simply never worried about it. I had growth that was faster than norm, I had briliant colors and lots of extension at night when I did feed before bed. My brain used to be about 5-6" diamiter during the day, and a night would expand to ovewr 12" my acro's would look smooth during the day but almost like milli's during the night. millies well they always have good extension .... go figure that out

my actual theory was it is a defence mechanisim, the ocean calms down at night, so maybe the intence wave action during the day was to much for the corals so they pulled in, at night when it is more calm they extend to catch food...

another question would be that thoes of you that have good polyp extension during the day... whats kinda flow do you have and do you vary it at night?

Steve