What is the concentration of CaCl in the Morton Salt pellets? Their Ice Melter product is a mix of CaCl and NaCl. They don't list the ratio on their website but perhaps the concentration of CaCl is lower than DowFlake, which is what Randy recommends using in his recipie.
Regarding your Ca; you are not following Randy's recipies as far as I can tell. Randy has 2 recipies for Ca solutions. Recipie #1 is for those with normal pH and recipie #2 is for those with higher pH and/or if you are dosing Kalk, which you have not mentioned doing.
In recipie #1: You are supposed to mix 2.50 cups of CaCl per gallon of rodi. So if you mix 4 gallons at a time, that would be 10 cups of CaCl, not the 6 you are using. This is probably why you are using so much...your solution is diluted and weak.
Regarding your Alk; it doesn't look like you're following Randy's recipies for this either. Randy has 2 recipies for alk solutions. Recipie #1 for those with normal pH and recipie #2 for those with higher pH (8.4+ , usually associated with running Kalk.)
In recipie #1: You are supposed to mix 2.25 cups of baking soda per gallon. You also should bake the baking soda in the oven to increase its potency. So if you mix 4 gallons at a time, that would be 9 cups of baking soda, not the 6 you are using. This is probably why you are using so much...its weak.
I don't know if you're baking your baking soda but your certainly not using enough of it.
Where did you find your recipie?
Here are Randy's recipies...written by Randy...
http://reefkeeping.com/issues/2006-02/rhf/index.php