You put 10g per bottle. Just looks like it's all in the sediment. Obviously not since you're measuring such high alkalinity. So if you were treating (say) 25l of water, how much would you need? 10g?Yes but the air has lots of CO2. Pressurising the bottles with pure CO2 speeds the process markedly.
The sediment is precipitated chalk not yet dissolved into the water - I did rather overdo it though because I wasn’t sure how much might be needed, in the end it looks like far less is needed than I used!