Lotus Water Precision Calculator

A local copy of the Lotus recipe math with the display rounding removed. Recipe targets stay in Lotus calculator ppm values; drop counts stay fractional so you can see the exact dose.

Lotus source page

Recipe Targets

Hardness ppm
Alkalinity ppm
Water Amount
Dropper Factor vs straight

Exact Drops

Concentrate Target Contribution Exact Drops Rounded Page Drops Ion Added

Weight Dosing

Water weight
Total concentrate
Finished batch
Concentrate Exact Drops Target Mass, g Target Mass, mg

This assumes water density is close enough to 1 g/mL for brewing use and uses Lotus' reported average drop size of 0.0716 g/drop.

Resulting Ions at Target Profile

Ion mg/L Source

Recipe Scatter Plot

Alkalinity, x-axis
Hardness, y-axis

This keeps the Lotus chart mapping: alkalinity is potassium plus sodium bicarbonate, and hardness is magnesium plus calcium. All recipe points are shown for context; the selected recipe is highlighted.

Unrounded Formula

DMg = HMg · W1000 · f4.5
DCa = HCa · W1000 · f4.5
DK = 2AK · W1000 · f4.5
DNa = 2ANa · W1000 · f4.5

D is exact drops, H is hardness target, A is alkalinity target, W is water amount in mL or grams, and f is the selected dropper factor.