Bone in CKD Alkali Response (BICARb Pilot Trial)

Inclusion Criteria (Pediatric Inclusion): * Children 5-17 years old * Estimated eGFR \>30 and \<90 ml/min/1.73m2 by CKiD U25 equations * Females of child-bearing potential must have had a menstrual period in the last month * Levels of PTH and alkaline phosphatase within 2x normal range and phosphorus within the normal range for age (per local laboratory reference assay) * 25-hydroxy Vitamin D ≥ 20 ng/mL * Females of child-bearing potential must be willing to use one form of effective contraception over the course of the study * Proficiency in English or Spanish * For participants \< 18 years, the participant and/or parent/guardian capable of providing informed consent and assent (assessed by the provider) Inclusion Criteria (Adult Inclusion): * Adults ≥ 18 years old * Estimated eGFR \>30 and \<90 ml/min/1.73m2 by the new CKD-Epi without race * Pre-menopausal women of childbearing age must have had a menstrual period in the last month * Levels of PTH and alkaline phosphatase within 2x normal range and phosphorus up to 5.0 mg/dL (per local laboratory reference assay) * Levels of 25-hydroxy Vitamin D ≥ 20 ng/mL * Women of childbearing potential must be willing to use one form of effective contraception over the course of the study * Proficiency in English or Spanish Exclusion Criteria (Pediatric and Adult): * Baseline potassium ≥ 5.5 mEq/L or prior history of hyperkalemia in the last 6 months (potassium \> 5.5 mEq/L) or currently taking a potassium lowering agent * Alkali t…