Was your alk and ca in the correct range before you started adding the two-part? What it sounds like is you did not keep up with the increasing demands of your tank and they have been depleted. You need to "reset" your levels......though it may not be a correct analogy I think of the two parts as dilluted componets of powdered buffers and liquid Ca such as Kents Turbo Ca. The two parts are used mainly for daily replacement and will only put it back to the level it was at "yesterday" in normal dosing as per directions. So if it was low yesterday, it will be low today with little or no change to the observer. You can get your Alk and Ca into the correct params using the two parts only, but you will probably have to pour in alot and waste it doing so and end up using it all.....most people whine about using two part at all because of the price, so I won't recommend doing that. But is the easiest and safest way for you to fix the problem, with the exception of the above consideration most have.
In a nutshell since you are adding new frags, your alk/ca demand is increasing as you do.....(hence the six cups and no movement, that is a little more than your daily uptake), you are only replacing yesterdays uptake. ALOT more needs to be added to overcome this deficiency.......
I "set" alk/Ca levels (10dkh/450ppm) when they are extremly low as in your case using a powdered buffer such as Kent or Proper Ph, and a liquid or pelletized concentrate Ca such as Turbo Ca. Once the levels are within the range you are looking for, put those in the closet and forget about them unless something like this happens again. After that switch back to the two part and adjust your daily dosing based on the uptake you determine from your daily alk test.......if the alk is going up, dose less......alk is going down.....dose more......pick a valuse of say 10dkh and try to keep it as close to that number as you can.......
However, the powdered buffers and liquid Ca are EASY to overdose, so go slow and test often(at the very least daily before you dose to adjust daily dose)........you can add more, a large swing could RTN your stuff. Hence why not many dose daily with this stuff, its harder to control the small changes that occur daily with these products, but possible......which leads to two-parts that additionaly add stuff like Mg in the process......
This is what I have done and works very welll, growth is great and consistent.
