Source: https://guthlabs.ai/docs/instruments/aquarium-volume-stocking-calculator/

instrument / verified-clean

# Aquarium Volume & Stocking Calculator

The current ledger marks this instrument verified clean within the source-bound verification corpus.

Status: **VERIFIED_CLEAN**Lifecycle: **verified-clean**

## Inspectable records

[01**Overview**Purpose and lifecycle](<https://guthlabs.ai/docs/instruments/aquarium-volume-stocking-calculator/>)[02**Mechanism**Method and assumptions](<https://guthlabs.ai/docs/instruments/aquarium-volume-stocking-calculator/mechanism/>)[03**Implementation**Binding and validation](<https://guthlabs.ai/docs/instruments/aquarium-volume-stocking-calculator/implementation/>)[04**Qualification**Evidence and errata](<https://guthlabs.ai/docs/instruments/aquarium-volume-stocking-calculator/qualification/>)

## Ledger state

The current ledger marks this instrument verified clean within the source-bound verification corpus.

**Area**: Everyday & Life

**Tranche**: tranche-4

**Evidence ID**: t4-280

**Ledger rows**: 1

No ledger note is attached.

## Review findings

The rectangular-tank volume equation is mathematically correct under the stated inch and US-gallon assumptions. The instrument cannot receive an unconditional PASS because the alternative stocking method is undefined and the selected heuristic is inherently approximate; the honest-label warning is appropriate but should be displayed prominently alongside the result.

### Formula and scope findings

- The volume formula is correct for rectangular tanks when L, W, and H are measured in inches: volume_gal = (L × W × H) / 231.

- The 1-inch-per-gallon method is a commonly cited hobbyist rule of thumb, but it is not a reliable general stocking formula and must not be presented as a safe biological limit.

- The specification offers either the 1-inch-per-gallon rule or a surface-area/bioload-adjusted method, but it does not define the latter formula, inputs, coefficients, or calculation procedure.

- The stocking calculation does not specify whether fish length means adult total length, standard length, or another measurement; adult size is mentioned but the aggregation rule is not explicitly defined.

- The formula calculates nominal gross tank volume and does not account for substrate, decorations, equipment displacement, fill height, filtration capacity, oxygenation, territorial behavior, species compatibility, or waste production.

### Unit assumptions

- Tank dimensions L, W, and H are positive measurements in inches.

- 231 cubic inches equals exactly 1 US liquid gallon.

- The test vectors use the explicitly selected 1-inch-per-gallon freshwater heuristic, not the undefined surface-area/bioload-adjusted method.

- Stocking capacity is interpreted as maximum aggregate adult fish length in inches equal to calculated gallons.

- Fish lengths are adult total lengths in inches, and current stocking is the sum of those adult lengths.

- Displayed gallon values are rounded to two decimal places only after calculation; stocking arithmetic uses the unrounded volume.

## Boundary hardening

**BREAK_CLAIMED** · SELF_FLAGGED

The specification exposes multiple failure hazards: zero dimensions can yield a numerically valid but physically impossible zero-gallon tank, enormous dimensions overflow to Infinity, the adjusted stocking branch lacks enough formula detail to compute an output, and negative dimensions can produce a physically meaningless negative volume unless an explicit sign convention and validation rule are implemented.

## Errata and corrections

No applied erratum is attached to this unique-name record.

## Inspectable example

4 review vectors are recorded. One source-bound sample is shown below.

````
{
  "inputs": {
    "method": "one_inch_per_gallon",
    "length_in": 48,
    "width_in": 13,
    "height_in": 20,
    "fish_adult_lengths_in": [
      6,
      4,
      4,
      2
    ]
  },
  "expected_outputs": {
    "volume_gal": 54.03,
    "maximum_aggregate_adult_fish_length_in": 54.03,
    "current_aggregate_adult_fish_length_in": 16,
    "remaining_rule_of_thumb_capacity_in": 38.03,
    "status": "within heuristic"
  },
  "working": "1. Tank volume = (48 × 13 × 20) / 231 = 12,480 / 231 = 54.025974... gal, displayed as 54.03 gal. 2. Maximum aggregate adult length under the heuristic = 54.025974... × 1 in/gal = 54.025974... in, displayed as 54.03 in. 3. Current aggregate length = 6 + 4 + 4 + 2 = 16 in. 4. Remaining heuristic capacity = 54.025974... − 16 = 38.025974... in, displayed as 38.03 in."
}
````

## Related workflows

No source-defined multi-instrument workflow membership is recorded.

## Sources and evidence

These pointers bind the page to evidence. They do not grant authority or collapse verification into deployment.

- `VERIFIED_LEDGER.json · VERIFIED_CLEAN`

- `evidence-tranche4/tranche4-results.json`

- `BOUNDARY_HAZARD_CATALOG.json`