Why does a small strength gap take so much concentrate?

Only the concentrate's strength above target does the work. A 50% concentrate against a 20% target works with 30 points. Closing a 1.5 point gap in 8,000 lb takes 8,000 × 1.5 ÷ 30 = 400 lb.

What if the batch tests stronger than spec?

Add water, and the calculator switches to it automatically. Water to add is batch mass × (measured − target) ÷ target, the same balance OxyChem uses to dilute 50% caustic to 20%.

Where does my refractometer or hydrometer correction go?

Apply it before you enter the result. Enter the corrected concentration on the same weight basis as the target. Temperature and density corrections belong to the measurement, not the mass balance, so this calculator does not scale readings.

Do I have to adjust a batch that is inside tolerance?

No, a batch inside the tolerance meets spec. The addition shown only moves it to the center. Centering is still worth it near a limit, because the next lab result carries its own measurement error.

Process Manufacturing calculator

Concentration Adjustment Calculator

Find how many pounds of concentrate or water bring a tested batch to target strength. You need the batch weight, the lab result, the target with its tolerance, and the concentrate's strength.

What this calculator does

Pounds of concentrate or water that bring an off-spec batch to target strength, by mass balance, and whether it is in spec now.

Formula used

Concentrate to add = batch mass × (target − measured) ÷ (concentrate strength − target), when measured is below target
Water to add = batch mass × (measured − target) ÷ target, when measured is above target
Batch mass after adjustment = batch mass + concentrate to add + water to add
Deviation = measured − target; spec margin = tolerance − |deviation|, negative when out of spec

Inputs explained

Batch Mass: Solution now in the tank, from load cells or the batch ticket.
Measured Concentration: Lab result by weight, after any instrument or temperature correction.
Target Concentration: Spec or recipe strength, by weight.
Concentrate Strength: Strength of the concentrate you would add, from its certificate of analysis.
Spec Tolerance, Plus or Minus: Allowed deviation either side of target, in percentage points.

How to use the result

Best suited to correcting a make-down after the lab titration, recovering a batch that tested over strength, fresh make-down from water and 50% stock.
Gives pounds, not gallons: convert with the liquid's density before you meter by volume. Does not check tank room or the temperature rise from heat of dilution.

Current U.S. benchmarks

The producer price index for industrial chemicals stands at 336.006 (BLS, Aug 2026), up 13.3% from a year earlier. Quotes priced off last quarter's material cost miss this move.
The U.S. has 14,543 chemical manufacturing establishments employing about 911,245 workers (Census County Business Patterns, 2023).

Common questions

Why does a small strength gap take so much concentrate? Only the concentrate's strength above target does the work. A 50% concentrate against a 20% target works with 30 points. Closing a 1.5 point gap in 8,000 lb takes 8,000 × 1.5 ÷ 30 = 400 lb.
What if the batch tests stronger than spec? Add water, and the calculator switches to it automatically. Water to add is batch mass × (measured − target) ÷ target, the same balance OxyChem uses to dilute 50% caustic to 20%.
Where does my refractometer or hydrometer correction go? Apply it before you enter the result. Enter the corrected concentration on the same weight basis as the target. Temperature and density corrections belong to the measurement, not the mass balance, so this calculator does not scale readings.
Do I have to adjust a batch that is inside tolerance? No, a batch inside the tolerance meets spec. The addition shown only moves it to the center. Centering is still worth it near a limit, because the next lab result carries its own measurement error.

Last reviewed 2026-10-01.