<blockquote><font size="1" face="Verdana, Helvetica, sans-serif">quote:</font><hr>Originally posted by Planoi:
<strong>Does anyone know what the 2 parts solution actually are? Most place would say it is calcium ion, but I thought it was not possible to have a free standing Ca.</strong><hr></blockquote>
The two part solutions are composed of two very different components. One is high in calcium ions, the other is high in carbonate alkalinity. There are counterions present in both solutions to give charge neutrality. When the two solutions are mixed in the aquarium, they give calcium and carbonate alkalinity in the correct ratios to form calcium carbonate (one mole of calcium per two equivalents of carbonate alkalinity) and the counterions present in the two solutions give a residual brine with the same composition as natural seawater.
These solutions work very well (my personal suggestions are either C-Balance but B-Ionic also works well for many.) The most significant problem with the solutions, aside from their significant cost, is the fact that the salt concentration in the tank will tend to increase faster than salt is removed in the form of saline skimmate solution. I would suggest that people using these solutions monitor the salinity in their system continuously, with a conductivity monitor. Alternatively, one can monitor salinity weekly with a high-quality method like refractive index.
Correcting the salt buildup is trivial. All you need to do is bail out an appropriate amount of tank water and replace it with purified water. It is the equivalent of a small partial water exchange in the system. The only problem is that without an online monitor, the salt concentration isn't "poking you in the eye" and it tends to build up silently in the system until someone hits their salt tolerance level and dies.
Craig Bingman