co3 is carbon trioxide. What are you trying to accomplish and how is that related to calcium depletion?
Technically, this is correct. CO3 is carbon trioxide.
CO3 is the carbonate ion.
The issue here is Epos means (CO3)2- and cc is talking about CO3. you're both right in different contexts. :)
No, you've misunderstood me. dKH is a measure of the Parts per Million of carbonate in a system. The parts per million in my tank and yours is exactly the same if we have the same dKH measure, however, it takes 5 times the chemicals to move your system 1 dKH than it does to move mine 1 dKH. So what i'm saying is this. When you put a big acro colony in your tank, let's say it uses 1 quarter teaspoon of carbonate a day. In a 125 that measures out to be roughly 1/6 of a dKH (you can check if you like). However, a quarter teaspoon of buffer in my tank = 2 dKH. (Again, you can test this if you like those numbers are accurate if you use kent superbuffer or brightwell's product or seachem reefbuilder). There are not the same amount of minerals in my tank as in a 125 because dKH is a measure of the Parts Per Million of the carbonate ion, that's why the testkit works for every system. However, there actually are roughly 1/5 of the minerals in my tank as in capts, it's exactly like I quarantined off 26 gallons of his system. They have the same parts per million of every element, however, the 26 gallons that were quarantined off only contain about 1/5 of the minerals of his total system.
All right, the fundamental debate here is one of concentration (dKH) versus absolute amounts of something (what us dorky chemists call moles). NOW, as a random example of this, let's say we've got 11 dKH. this is equivalent to appx 4 milliequivelants/L, or about 200 ppm calcium carbonate. this means that if your test reads 11 dKH, then in theory, up to 200 mg of calcium carbonate/kg of water is available for corals to use. This is essentially a measurement of concentration, and doesn't depend on tank volume. The number of molecules of calcium carbonate, however, depends on volume, which is where Epos is coming from. The difficulty here is, we can't directly measure exactly what sources of carbonate are in our tanks, so we can't count the number of molecules very accurately. So it's pretty meaningless for us.
SO, to answer the question Epos, if you're adding these big SPS colonies to a small tank, you'll also see a drop in calcium which will mirror the drop in carbonate. both of these parameters are needed for corals. So, even if your calcium levels are stayin stable now, you'll have to start dosing calcium and alk, and/or do more water changes, to keep up with the demand for both calcium AND alkalinity. That's if your system is balanced within the correct (ie, close to natural) ranges for calcium, pH and alkalinity. If it isn't, then you can dose alkalinity; however, doing 4 dKH a day is impractical because the carbonate will precipitate out way too fast (like, in the tubing and stuff) cause you'd have to have a pretty concentrated buffer solution to do it that way.
Hope this helps clear up some of the debate....