I bought six Red Cherry Shrimp about six weeks ago. They were all juveniles when I bought them (about 1-2cm) but seem to have grown and coloured up nicely in that time

-How long is it before I can expect/hope to see eggs? (Given that they were juveniles six weeks ago)
-When they do produce eggs does the 'saddle' on the females disappear, or stay where it is?
Also, a few days ago one of the females moulted but seemed very weak afterwards. Within a few hours she had passed on

-Does anyone have any ideas as to why the shrimp may have died so soon after a moult?
Also my water is quite 'soft' - so would it be safe for me to add either/both some 'florida crushed coral' or some cuttlefish bone to help increase hardness/calcium levels? Or could I cause a Ph crash/spike by doing so?
(Please correct me if I have misunderstood what these things do, as I am still learning about water parameters)
Does anyone have any breeding advice? (changing temperatures, different foods, etc) Or am I just expecting too much too soon?
Thanks in advance
