I have been making my own KALK (lime water) to top off my tank. The question I have is this, do you need to have the storage container its in tightly sealed. I have a liter bottle I does it from which is vented so it can not be sealed tightly but, does the storage container have to be? I noticed the white stuff on the bottom seemed to accumulate more over a few days it was in a bucket and this was after it all settled in the first couple hours. I was thinking that if this stuff on the bottom is accumulating that it maybe pulling the calcium out of the solutions. I read that CO2 caused this white stuff. Am I right in thinking it should be covered and if its not the concentration of calcium is getting less? Also does anyone know if a high ALK will cause less calcium, my ALK is over 14??!!!