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 :mrgreen:

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

Steve, I guess my question comes about by the fact that for the first 3 or 4 months, every piece I had displayed full PE during the day. Now, 905 do not, with no obvious reason, other than the one water change I did with different salt (which affected my alk). Ok, somewhat obvious perhaps, but until I get my alk back to where it was, unproven hypothesis :)
So the tank has matured, the zeo system has had a chance to develop (or over develop with my dosing schedule), lighting is more than sufficient, feeding has been constant, no fish additions at the before/after point, so it's a bit of a mystery. Not so much a concern, but more a puzzle that I'm curious about.

ya it would be nice to have a fish researcher do a 5 year study on it and get a difinitive answer :mrgreen:

you doing any dog stuff in the interior this year?

Steve

not unless Cloverdale has moved closer to Kamloops :)

I deed, I don't have a lot of flow, nothing strong, maybe that's why I have great polyp extension any time.

A lot of people say that with SPS you need strong flow, but mine is very weak and I still have great growth, color and extension in my SPS. My alkalinity is always low, around 6.5.

I'm guessing this has some influence on PE. The one difference from before/after for me is my alk is higher. I saw a tank today with huge PE, alk was at 6...

My PE is always great day or night.

Alk is always around 7.5 - 8

Just tagin along here :popcorn:

I always did keep my Alk a couple points higher than most people also...

Steve

My PE is decent during the day, and crazy at night. Alk is low - 6 - 6.5 dKh, Ca 400 - 440, Mg 1350.

I noticed before that with an angelfish in the tank for a few weeks there was less PE on a few pieces it liked to nibble on, but other corals it left alone always had pretty good PE.