Kalk Reactor....

Calcium and alkalinty are dance partners.  They both decline at (more or less) same rate in your tank.  They are depleted through calcification via:

Ca + CO3 = CaCO3

Ca and CO3 are dissolved in your water while CaCO3 is a solid (aragonite or calcite)

So I suggest your long term additive should be one that adds both.

Kalkwasser, calcium reactors and B-ionic all add equal amounts of both, without disrupting the ionic compostion of the water.

Buffer (or baking soda) and calcium only additives (such as Turbo Calcium) will increase either alk or calcium but long term usage will disrupt your water's ionic composition.

I use buffer or Turbo Calcium to get my levels where I want to keep them then I use a "balanced" additive (kalkwasser and calcium reactor) to maintain them.  It's not perfect so every couple months I have to add either alk or calcium to help "boost" it back into my operating zone.  In my case I usually have to add a little Turbo Calcium every couple months.

Easy. 

Adjust your calcium and alk to where you want to keep them.  Then begin dripping 1/4 of your daily make-up water as kalkwasser over night, check your pH periodically during the drip.  Stop if your pH get's higher then 8.4 and either drip slower or reduce the amount of kalk dripped.  Recheck your calcium and alkalinity after about a week of this (actually, the alkalinity is the most important one to check and I usually don't check calcium all that often).  If the alkalinity is higher then last week then you're adding too much kalk and you can back off on the amount dripped each night.  If the alk is at the same level as last week then your set, keep doing what your doing.  If the alk is lower then last week then increase the amount added each evening (keeping an eye on pH).  If you do this for one week and post what your starting alk level was and what it is after a week of kalk, I can give you a pretty good "guestimate" of how much you should add or decrease.  Or just do it yourself.  You'll zero in on the right amount after a few weeks.

Good luck.

hmmm... Your water should not be cloudy for 20 min after adding buffer.  If you're using a commercial buffer (Reef Builder, right?) or baking soda you should not see any cloudiness.  If you're using washing soda there will be some initial cloudiness in the local area where you dump it, but it should turn clear within seconds.  Is the RO/buffer mixture crystal clear with no solid particulates?