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Wasabi,
Prolly will not find much in the way of documentation that Ca at 450 and alk at 11+dKh will show noticable documentated increases in calcification rates in closed systems. The basis for running systems at as close to saturation as possible centers on pulsed dosing systems where the measured Ca and alk did not necessarily reflect the average Ca, rather a generalized number based on calcium after dosing or delivery rates that did not result in CaCO3 salting out of solution or exceeding max "poisoned" crystal saturation and doing the same. Now that we have pretty good methods of maintaining these levels with consistant delivery (reactors and controllers), we can consider average Ca levels rather than the max level after dosing. In most systems, the corals we keep are usually not growth rate limited by the concentration of Ca or Alk (both equally necessary to form skeletons) so long as we maintain at least minimum seawater quality levels of these elements. It is usually other factors that limit growth or skeletalization/ calcification rates, primarily either quantity or quality of our lighting and current and nutritional issues. The Ocean still out performs our closed systems for several reasons (including several we are prolly oblivious to), where corals have evolved to utilize the concentration of nutrients and minerals at the concentrations found there. Keeping Ca and Alk at these "holy grail" levels is just cheap insurance, and has been consistantly demonstrated in most advanced closed systems to have a beneficial positive growth inrfluence on captive-raised corals. I am not so sure that this is because it is easier to do this in balanced measure at these higher levels (at saturation) than it is to try and dial in the numbers at 350PPT Ca and 6 to 7 dKh alk. As there has been no demonstrated down side to keeping closed coral propagative systems at the saturation levels (other than premature pump failure, etc due to abiotic CaCO3 ppt and the expense potential), maintaining these high levels is just a means to an end, and I for one am always looking for the low-tech ease-of-use aproach to keeping these creatures.
Is it mandatory to maintain these high levels? Prolly not, but it IS much easier to do that than it is dialing into the actual levels of the ocean, and once again, it doesn't appear to hurt, and it may actually have some benefit in increasing keletalization/calcification rates in our closed systems for these corals.
HTH
__________________
Tom <"))))>(
(TDWyatt)
Wise men speak because they have something to say; fools, because they have to say something. -Plato
Last edited by tdwyatt; 09-15-2003 at 09:45 PM.
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maybe i am just not that advanced.
