Water chemistry question

[asylumdown]

I'm hoping someone with a background in chemistry can help me out with this, as I'm not sure if this is normal.

I use an auto-doser to keep my calcium and alkalinity levels where they're supposed to be. The weird thing is that I'm finding I need to dispense nearly double the amount of alkalinity solution every day than calcium to keep levels where they're supposed to be.

For example, if I make a solution using a product like turbo calcium, or even straight up calcium chloride with one cup per gallon of water, and I make another solution of one cup of baking soda per gallon of water, I'll need to dose almost exactly double the amount of baking soda to keep my dKH at acceptable levels compared to calcium

I thought that corals used calcium and carbonate in equivalent proportions? Is there something else going on that I'm not aware of? Or does this have to do with the native concentrations of 1 cup of baking soda vs 1 cup of calcium chloride?

Also, I recently switched to baking my baking soda so I was dosing carbonate instead of bicarbonate. I didn't realize that the dosing pump hosing for the carbonate had gotten blocked, and I had just doubled the concentration of my calcium solution in the current batch of solution to try and cut back on the number of times I need to make fresh solution. I didn't pay attention for a few days and when I tested, my alk was way down around 6.5 and my calcium was sky high at 485. When I fixed the tubing and started increasing my dKH, half of my pumps failed because of spontaneous precipitation (thank god for vinegar..)

Was this a) because the increase in alkalinity pushed the already super high calcium out of solution or b) because I was using carbonate, which apparently precipitates out of solution easier? (My magnesium levels were a little low at 1150 at the time).

Any insight would be greatly appreciated. I'm no chemist and I'm having a hard time wading through the online materials.