Bone in CKD Alkali Response (BICARb Pilot Trial) (BICARb)

Inclusion Criteria: Age ≥ 5 years old For children: Estimated eGFR >30 and <90 ml/min/1.73m2 by CKiD U25 (For Pediatric participants) equations For adults (≥18 years old): Estimated eGFR >30 and <90 ml/min/1.73m2 by the new CKD-Epi without race (For Adults) Females of child-bearing potential must have had a menstrual period in the last month For participants < 18 years, the participant and/or parent/guardian capable of providing informed consent and assent (assessed by the provider) Proficiency in English or Spanish PTH and phosphorus levels within the normal range 25-hydroxyvitamin D ≥ 20 ng/mL Women of childbearing potential must be willing to use one form of effective contraception over the course of the study Exclusion Criteria: Baseline potassium > or = 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 therapy within the prior 12 months Baseline ECG with abnormalities associated with increased risk of arrythmia, excluding left ventricular hypertrophy Baseline serum bicarbonate levels <17 or > or = 30 mEq/L Serum calcium <8.6 mg/dL, adjusted for serum albumin Significant comorbidity causing acid-base imbalance (e.g. active cancer requiring chemotherapy, chronic liver failure, moderate or severe chronic obstructive lung disease, New York Heart Association class 2 or greater congestive heart failure, obstructive sleep apnea requiring nightly continuous positive airway pressure, active glomerular disease requiring immunosuppressive therapy, intestinal malabsorption or celiac disease) Plans to relocate out of the area in the next 3 months Urine pH > 8 or history of nephrolithiasis Lower extremity amputations or non-ambulatory Metabolic bone disease not related to CKD (e.g., Paget's disease, primary hyperparathyroidism) Endocrinopathy: untreated hyper or hypothyroidism, Cushing's syndrome Medical diseases that can affect therapy (severe myocardial damage, acute dehydration, delayed gastric emptying, esophageal compression, or intestinal obstruction or stricture) Use of bisphosphonates, denosumab, teriparatide, abaloparatide, romosozumab, raloxifene, estrogen or testosterone replacement therapy, glucocorticoids within the 12-months prior to enrollment Previous bilateral wrist and tibia fractures Solid or liquid organ transplant On dialysis or with rapidly deteriorating kidney function or expectation for transplantation or initiation of dialysis in less than 3 months Pregnancy or breastfeeding Prisoners or institutionalized individuals Unwillingness to provide informed consent