SDI Tank Sizing Calculator

Use this tool to determine the right SDI tank size for your application. Enter your water usage and quality details to get a professional, step-by-step engineering report.

Step 1: Your Water Usage

Reference the chart below to estimate your typical flow rate and see the USG capacity for each tank model.
Application Flow Range (GPM) Recommended Tank Model USG Capacity*
Small lab, glasswasher 1–5 8x44 (1.0 ft³) 1,200–1,500
Medium process, small production 5–10 14x47 (3.5 ft³) 3,500–4,500
Large process, multiple outlets 10–20 21x62 (7.0 ft³) 7,000–9,000
Industrial, large system 20–40 Jumbo (42 ft³) 42,000–50,000
Select Tank Model:
Enter your typical flow rate (GPM):
Enter the average flow in gallons per minute (gpm) your process or equipment uses.
How many hours per day do you use water?
Estimate the number of hours your system runs each day.
Number of Tanks (in series)
How many tanks will be used in series (one after another)?
*USG capacity is an estimate and will be refined by your water quality in later steps.

Step 1b: Resin Type

Industry field estimate: 10,000 grains/ft³ (new), 9,000 grains/ft³ (regenerated).

Step 2: Water Quality (Optional)

If you have a water quality report, enter the conductivity. Otherwise, leave the default.
Advanced Options: For most users, the default water quality values are accurate. If you have a water analysis or lab report, you can enter your own TDS, CO₂, or grains loading values for a more precise calculation.
Assumptions (edit in Advanced Options):
  • TDS: 50 mg/L
  • CO₂: 2 mg/L
  • Grains Loading: 3.0 grains/USG
  • Resin capacity: 10,000 grains/ft³

Step 3: See Your Results

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