I have been having troubles with my Ca and Alk. My Ca has been low for a while now, averaging about 360ppm and my alk is about 8 dkh. However, I was unable to raise my Ca no matter how much I dosed. My dosing regime was to dose Ca and Alk at the same time. After reading that article about Alk, Ca and Mg, I learned that adding Ca reduces Alk a little and adding Alk reduces Ca a little. Also, that in order to raise one or the other, you need to dose them separately, I think. Anyways, I dosed Ca by itself and test a few hours later and it was up to 430ppm, good right. However, my alk had fallen to about 6 dkh. So I dosed Alk, then tested both later on and my Ca was about 390ppm, and Alk about 7. BTW, my Mg is 1350 so that's not the problem. I just want to know how you dose a two part system? Thanks.