Carbon Dosing Calculator

How much vodka or vinegar should I dose in a reef tank?

Choose a protocol before choosing a number. A carbon-content calculation can compare bottles, but it cannot tell you the bacterial population, oxygen demand or nutrient export capacity of your aquarium. There is no dependable “add this many milliliters to remove that many ppm” relationship for a living reef. The planner above scales a published schedule, identifies its source, and stops presenting an increase when your observations contradict it.

The default schedule follows Miami Reef’s charts, revised October 2024, for 40% ABV vodka or white vinegar at 5% acidity. These are hobby protocols, not controlled safety trials. For 100 L, their first-week daily amounts are 0.826 mL vodka or 6.604 mL vinegar. Subsequent rows are conditional, and the fourth week is a review rather than another calculated increase.

Use actual circulating water. A nominal 100 L aquarium holding 75 L receives 33.3% more per liter if you calculate from the box size. Include water in the operating sump, then subtract displacement; the true water volume calculator handles that accounting. A saved tank supplies this starting volume, while a shared calculator link takes precedence.

Why do the vodka dosing charts disagree?

The 2008 Walton and Bjornson method starts at 0.1 mL per 25 US gallons for three days, doubles that rate for the rest of week one, then adds 0.5 mL to the whole system’s daily dose each week. For 100 US gallons, week two is 1.3 mL/day. Scaling that later increment by each 25 gallons instead gives 2.8 mL/day. Those are different methods.

The newer chart used here deliberately changes both the starting rate and how the ramp scales. Its first week for 25 US gallons is 0.781 mL/day of vodka. Do not splice the start of one chart onto the increases of another. If you are already dosing, compare the selected protocol with your recorded history; a new calculator visit does not mean your bacteria are back at day one. We show only three weeks and withhold escalation at a stop condition.

How much vinegar equals 1 mL of vodka?

On carbon content, 1 mL of 40% ABV vodka matches about 8.23 mL of vinegar labeled 5 g acetic acid per 100 mL. Our calculation uses ethanol density near 20 °C, the two molecular formulas and the stated concentrations. Changing either bottle changes the answer. For example, 10 mL of that vodka carries the carbon in 82.28 mL of that vinegar.

Computed from ethanol C₂H₆O, acetic acid C₂H₄O₂, and pure ethanol density 0.789 g/mL at 20 °C. Vinegar rows use mass/volume acidity; no assumed vinegar density is needed. These are chemical comparisons, not substitution instructions.

The chart’s eight-to-one dosing ratio is an empirical protocol choice. The converter’s 8.228-to-one result counts carbon atoms. They answer different questions. In his own discussion of switching sources, Randy Holmes-Farley describes tank-specific responses, including cyanobacteria. Equal carbon does not establish equal biological response, the same pH effect over time, or an interchangeable maintenance dose.

Does “40% vodka” mean the same thing as “5% vinegar”?

No. Vodka’s ABV is a volume fraction of ethanol. One milliliter at 40% ABV contains 0.4 mL of pure ethanol equivalent; applying ethanol’s density gives 315.6 mg ethanol. The carbon part is 164.56 mg. Using 40% as a mass fraction skips a necessary conversion.

The FDA vinegar labeling guidance expresses acid strength as grams of acetic acid per 100 mL. On that basis, 5% means 50 mg acid per mL, of which 20 mg is carbon. Some specifications instead give grams per 100 g. Select the mass-percent option only when that is what your product states, and enter the solution’s density.

How do I calculate a NOPOX dose for my tank?

Use the rate selected from the current instructions for your bottle and aquarium. Red Sea’s Algae Management manual has different instructions for mixed reefs and lower-nutrient systems. The NOPOX mode here is a volume scaler: entering 2 mL per 100 L for 200 L gives 4 mL/day. It does not choose a nutrient band, forecast later readings or increase the rate next week.

We consistently use the metric label basis, because 25 US gallons is not exactly 100 L. Red Sea’s manufacturer support guidance identifies 3 mL per 100 L as the maximum daily rate and directs users to support if nutrients do not respond. This tool rejects higher rates. The separate, editable stop floors can be stricter than a product regimen; it is not intended to automate an ultra-low-nutrient system.

NOPOX is not assigned a vodka equivalent. The manufacturer describes a mixture of carbon compounds without a complete quantitative formulation on the cited product instructions. A forum recipe resembling its behavior does not establish the contents of the bottle. Choose its label mode; do not substitute a guessed carbon percentage into the converter.

Will carbon dosing lower nitrate and phosphate together?

Not in a reliably fixed ratio. Carbon can support biomass growth and, in suitable low-oxygen locations, denitrification. Nutrients incorporated into biomass still need to leave the system or remain retained in growing organisms. The nutrient readings also reflect feeding, other export, uptake and exchange with surfaces. A starting nitrate test therefore cannot supply all the variables needed to predict tomorrow’s result.

Record both nutrients at comparable times, along with the actual daily dose. An unchanged reading can conceal opposing input and export, while a sudden low reading needs confirmation before another adjustment. The reef parameters guide provides context for choosing your own goals. If nutrients are already depleted, escalating carbon is the wrong direction; nitrate and phosphate dosing addresses measured shortages with known-strength additions.

Why is nitrate not falling, or phosphate still high?

Check the measurement and the export before increasing the dose. Confirm the test’s reporting units and resolution, the bottle strength, the actual delivered milliliters and the true water volume. Review feeding, accumulated waste and skimmer performance. A pump setting is not a measurement of what came out of its tube.

When one nutrient is near the test’s lower limit, do not force the other down with an ever-larger carbon addition. Our planner uses the readings as stop conditions, not as a ratio to chase. “More carbon” also cannot correct an uncertain phosphate test. For a quantifiable correction by replacement water, compare the reef water-change tool; its dilution model has a clear, different set of assumptions.

What if the water turns cloudy or fish breathe heavily?

These observations outrank a printed calendar. Carbon additions can stimulate respiration and lower available oxygen. Pause dosing, increase aeration and surface movement, and check the skimmer. Investigate the condition before restarting. Selecting distress above removes the numerical schedule; a copy of an earlier PDF cannot know that the tank has changed.

The original vodka protocol explicitly calls for observation and warns against doubling after a missed dose. Measure with equipment that resolves the amount shown. If a pump cannot deliver a tiny portion reliably, rounding it up changes the dose; use suitable measuring equipment or reassess the delivery method. The portions setting divides a daily total, so two portions do not mean twice the daily amount.

Is this the same as planted-tank liquid carbon or activated carbon?

No. This page concerns organic-carbon additions in marine nutrient management. Flourish Excel and planted-tank liquid fertilizer have separate product instructions and purposes. Activated carbon is a solid filtration medium; it is not the liquid food source represented by these calculations. Neither belongs in this source converter.

Before switching an existing reef routine, keep the chemical comparison and the husbandry decision separate. The converter can show that two amounts contain the same carbon. It cannot establish whether to keep, lower or replace today’s dose. Preserve the testing history, change deliberately and evaluate the aquarium’s response.

Sources and calculation limits

Source review: November 4, 2026. Schedule numbers were checked against the author’s vodka chart and vinegar chart, revised October 2024. The calculator interpolates their unrounded linear rates to actual water volume. The three-week horizon is a planning limit, not a maximum safe lifetime dose.

Carbon math uses the formulas cataloged by NIST for ethanol and acetic acid, conventional atomic masses, and Sigma-Aldrich’s pure-ethanol density. These physical references identify substances; laboratory alcohol is not a recommendation for aquarium use. All displayed chemistry ignores trace ingredients and temperature-dependent volume changes. NOPOX composition and any nutrient-removal forecast are deliberately unspecified.