Kalk question

[acpoweradapter]

So, I've been dosing kalk for the past two months and it has kept my ph steady at around 8.15-8.25 and during the first few weeks I would check the calcium and alk just to make sure it was all good and calcium was 480 and alk was 7.8 to 8. And I didn't check it for the past month, but I noticed that my frogspawn was not opening up as much as it used to so I checked it and my calcium is 490 which I figured is fine, but the alk has dropped to 6.8. The ph is still 8.2. Is that normal when you dose kalk or is something wrong?

 

[Playa-1]

If you've done a water change since you checked it last, then it could be your salt mix throwing your numbers off. Kalk is a balanced alk and calcium supplement. So if your alk is dropping compared to your calcium, I would think that maybe your tanks calcium requirements are on the low side. Your tanks calcium requirements might be low enough at this point to where you may not need to dose Kalk. I would suggest you check your water parameters more often and make adjustments as necessary to keep them stable. Your 10% water change every other week is a good opportunity to check your water parameters and make adjustments as necessary.

http://www.advancedaquarist.com/issues/nov2002/chem.htm