Aquarium Volume & Stocking Calculator mechanism

Model scope

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.

• 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.

Units and conventions

• 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.

Inspectable vector

One of 4 source-bound review vectors:

{
  "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."
}

Failure boundary

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.

Other records

Sources and evidence

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

• VERIFIED_LEDGER.json
• evidence-tranche4/tranche4-results.json
• BOUNDARY_HAZARD_CATALOG.json