So I go to work and come back and find a bazillion posts.
Mike;
Of course, lets not try to exaggerate, when we say K has no effect on growth. I believe I said as long as it is a reasonable K.
That came out wrong, I was agreeing with you. I was saying that others maybe exaggerating that K make 0 dif at all. So UPS will not be at your door
First Mike nice piece from Porter, now I don't have to type all of that from Sorokin
Same for the other post before it it
In general, photosynthetic corals receive about 60-70 % of their daily need from light. Some need more others need less. When one speaks of P:R values they need to be careful. There are a number of ways of doing this. A straight P:R value for corals does not take such things into consideration such as mucous production, while others do and is the reason behind some of the labels, i.e, P :R, Pt/Mt, CZAR, etc. A straight P :R for some corals may be 1.2 ( = 120%) of their daily needs by light alone but when you throw in mucous, mobility energy it drops to a "corrected" P :R,which may now be only P :R .8 ( 80%). Here is just one example from Sorokin
"The ratio Pt/Mt, calculated per day, decreases much faster with depth and the decrease in light than these ratios, calculated per hour, mostly because of the shortening of the light period of day at depth. For example, in the coral
Stylophora pistillata the Pt/Mt per day at a depth of 2m was 2.0 and at depth of 45m it was 0.4. Thus, at the depth of 45m this coral may compensate its energy expenditures only by about 25-30 % (counting expenditures additional to respiration).The rest the coral should compensate for by heterotrophic feeding."
Sorokin is a wealth of info, more than one would ever want to know. Ex ; SED's of corals, table after table of P:R, rhythm of diurnal activity, polyp size relationship, fed rates and how much of plankton,
Artemi, bacterial feeding, DOM, POM feeding, ciliate feeding, elements of food balance rates of feeding ( on many corals), and on and on and on........
I have always said corals need to be fed, they can not survive without supplemental feeding of some kind. And those capture tentacles are there for a reason, not just looks. And those capture tentacles do not need nematocysts to fed with. There is a 30 page chapter in Sorokin just on feeding and everything that is involved. And another 30 more so on "light" feeding and everything that is involved
This is not a simple or easy subject it is very, very complex, with many other variables that can shift things i.e, salinity temperature, currents. location, depth, etc..
Other stuff;
Many corals come out at night to feed for a big reasons, that is when the plankton count is the highest.
Actinic lights were not introduced into this hobby to make the tank look nice, that is a myth. The were brought in for the reason that they produced blue light, based on the fact that most of the light is absorbed in the first meter of water, leaving mostly blue behind. This however, is more on the order of the deep ocean where the water is blue. Ever seen a blue reef, they are usually some shade of green or blue-green. The biggest peaks are in the blue 380-450 nm, then the red 650-700nm with a low peak in the green 550-600nm, in ***general***. Ex,
Favia on one species was peaks at 440, 540 and 670 nm
Craig
On the subject of anenomes. I know from my own observation, that my photosynthetic BTA grows substantially more when I target feed a couple of times per week when compared to the same lighting, but letting the Clown Fish to feed it.
Are my experiences close to what the studies say?
Yes, they need to be fed also. However, clownfish don't feed their anemones, that is a myth, people just THINK they are. I have watched them feed dead barnacles. They are just moving **their food to a safe place, which really isn't so safe as the anemone just eats it. This so called feeding by clowns is nonexistent in the wild.
I'm sure I forgot something but time for bed
