Calcium level help

Hey guys so Ive had my tank for a couple months now. I havent done any dosing until this week. I do water changes every sunday. So my salt mix usually makes my calcium around 330-340ppm. I tested my water last monday for Calclum and KH. My calcium droped from 330 to 300 and my dKH droped from 9 to 8. I slowly increased my calcium to 340-350 ish the same day. Now I tested my water yesterday (friday) and my calcium was 320 ish. I dosed my aquarium yesterday, to increase it by 40-50ppm. I used the same process as acclimation so im not adding it all at once. I did this within 3-5 hours. Now I tested my aquarium today....My Calcium is still at 320-330 ish! I seem to have hit a bump on the road. I do not want to add anything else incase im missing some critical information that I am not aware of. Can anyone help me with my problem? Any recommendations ? Should I keep dosing calcium or chill out for acouple days? For inverts I have 1 cleaner shrimp, 1 pistol shrimp, 1 emerald crab and 4 hermits. I currently have only three soft corals which are Green Star Polyp, Finger Leather Coral, & Anthelia. Now all my corals are doing great & my inverts are perfectly fine. My tank physically appears to be healthy. My PH is 8.0, ammonia is 0, nitrites are 0 and ntirates are super low.... lower then 2ppm. I Should also add that my tank maintains a salinity of 1.24-1.26. I aim for 1.25.