Hello, I have a new RedSea reefer 300 that I set up over two months ago. I used caribsea sand and art rock as seen in the picture. I used the Red Sea coral pro salt which is supposed to have 10-12Dhk of alkalinity. There are no corals to suck out the alkalinity. However each week I see my alkalinity drop to 4s. I’ve added dosed BRS alkalinity multiple times and got it back to around 8.5. However I notice like a 0.4 drop each day and settles in the low 4s each week. I’ve tried dosing multiple times, done water changes. Still the same. Trying to figure out why this is happening. Any help is greatly appreciated