Everything seems to be thriving, the level is very consistent, so I’m not going to attempt to mess with anything.
My one female is still berried, we’re at about the three week mark since I first saw the eggs. Lots of moss for them to hide under.
Your Caridina should be fine with that PH, it may be the new substrate and setup causing it to be a bit lower than you expect but if my previous attempt is anything to go by it should creep up very slowly as the tank settles and matures! My prior tank setup started at PH5.5 and all was well, and the current setup is PH5 though the next colour change is PH6 so it could be anywhere between those figures???
Hope the berried female is still doing well, or has she had her babies yet? Babies will be microscopic and hide to start with.