I Have Had Two Blood Tests Showing Stage 2 For

I have had two blood tests showing Stage 2 for CKD. I am wondering how safe it is to take Citrucell powder or tablets, Mira Fiber, and another supplement I take nightly that has elemental magnesium and potassium. (I could get you the amounts if you need it.) I need these to prevent severe constipation, which causes diverticulitis symptoms!
I also had a kidney stone in May (my first) and an now off calcium supplements, salt, and told to drink LOTS of water. I am a 67 yr. old female.