I am not too familiar with those salt brands. I personally use Instant Ocean and am very satisfied with their product. Also, are you adding these products on the same day? If so, there is a big part of your problem. The relationship between these three factors is kinda like a seesaw. One goes up, the other goes down. The products that i use for dosing are both seachem products, Reef Builder, and Reef Advantage Calcium. These are all that i use. I dont use kalk, nor have i ever. With these two products, it is very easy to determine what to add, how much, and how often.
Here is one thing you can try, first off stop adding all chemicals and begin doing small (5-10%) water changes maybe twice a week until you have pretty much changed all the water in your tank. Once you have done se, begin adding you calc buffer in small doses daily and test your water daily. Once it is where you want the level, stop adding but continue testing. This will determine your consumption rate. Then once again, slowly add your buffer until it is where you want it and determine how much you need to add to keep it stable based on your consumption rate. Then repeat this process with you alkalinity, however be forewarned that when you add alk buffer, your calc will fall so you will have to adjust how much calc buffer you are adding, it will be probably slightly more. Once your calc and alk ar both where you want them, and you know how much to add to keep it stable, your pH should follow and stabilize. I have never found a need to add any pH buffer. Primarily because Instant Ocean salt has a pH of 8.2, and my alk buffer stabilizes that. Keep in mind also that your calc buffer and alk buffer should never be added on the same day. Also in the midst of this process, i would stop using the kalkwasser until you figure the first half out. Once you do that and feel comfortable with it, then i would throw in the kalk and see how much of that it takes to keep things stable. I dont use kalk so i am not really familiar with it, but i am pretty sure that is why your pH is fluctuating. Kalk has a caustic effect on pH where as the seachem products do not.
So all in all, the minimum that i would do is switch salt brands. I think that this is a portion of your problem. Secondly, this is a difficult process that literally took me well over a month to figure out. But once i have, things have really taken off in my tank. I hope that this helps you, and i just want to add that i am by no means an expert on this matter. That would be Broomers job. So if he or anyone else has anything to add to this, please by all means do so.
and alk at 3.80. Even my pH has stayed stable at 8.3 Thanks for all the help guys, my tank is growing like a madman