Changelog

Tank-size landing pages, homepage quick reference, guide diagrams, and visual QA pass.

• Added/tanks — 52 dedicated pages for every common aquarium size. Each one shows real water volume, filled weight (salt + fresh), recommended glass thickness, heater wattage, and substrate at 2" depth, all pre-calculated from the calculator engines. Standard Aqueon / Marineland sizes, Innovative Marine NUVO, Waterbox Rimless, Red Sea Reefer, and the common "I have an X by Y by Z tank" dimension queries.
• AddedHomepage 'Common tank sizes' widget — 12 popular sizes linked directly to /tanks landing pages.
• AddedFactual SVG diagrams in the nitrogen-cycle, two-part-dosing, and lighting (PAR vs PUR) guides. No clip art, no AI illustration — just labeled vector diagrams of the actual chemistry and physics.
• AddedThis page (/changelog).
• ImprovedFull visual audit at desktop (1280 px) and mobile (390 px) — header collapses cleanly, no text overflow, TL;DR boxes legible on both viewports, tables scroll horizontally where needed.

SEO polish: TL;DR boxes everywhere, real HowTo and Article schemas, FAQ-rich hubs, anonymized author.

• AddedTL;DR boxes on all 21 calculators and all 8 parameter pages. Bottom-line answer in two sentences before the math.
• AddedReal HowTo JSON-LD schemas on every calculator (step-by-step), and Article schema with datePublished + dateModified on parameter and guide pages.
• AddedFAQ sections on /calculators and /parameters hubs to capture long-tail queries.
• AddedInline internal links between related calculators, parameters, and guides — so the alkalinity calculator links to the alkalinity reference and the two-part-dosing guide, not just a generic 'see also' block.
• AddedLegal pages: /privacy, /terms, /disclaimer, and /contact.
• ImprovedCustom branded 404 page ('That page is bottom-fed.') with quick links to calculators, parameters, and guides.
• ImprovedHeader nav points 'Guides' to /guides hub instead of a specific guide. Methodology hidden on narrow mobile to prevent wrap.
• ImprovedAll schema author entities reduced to Organization only — no person attribution anywhere on the site.

SEO expansion: 14 new pages, per-page OG images, embed widgets, llms.txt.

• AddedCalculators: gravel, sand, aquarium glass thickness, AFR (alk freezing range), Red Sea Foundation dosing, return-pump turnover, salt-mix mixing, BRS alternative pricing.
• AddedGuides: aquarium nitrogen cycle, reef-tank lighting PAR vs PUR, vinegar (carbon) dosing, ICP testing for reef tanks.
• AddedPer-page OpenGraph PNG images (36 total) — generated locally with Space Grotesk + Inter + JetBrains Mono. No 'made with AI art' look.
• AddedEmbeddable widget endpoints at /embed/<calculator> for every calculator — noindex, lightweight, 'Powered by ReefCalcs' footer for attribution.
• Addedllms.txt at site root — explicit machine-readable description for AI crawlers (Perplexity, ChatGPT, Claude).

Initial release.

• Added13 calculators: volume, weight, alkalinity dosing (Randy Recipe #1, BRS, BRS Lite), calcium dosing (CaCl₂ + soda ash), magnesium dosing (Recipe 3A), kalkwasser, salinity / specific gravity, salt-mix consumption, stocking (inch-per-gallon, with caveats), reef health dashboard, CO₂ / pH (planted tank), heater wattage.
• Added8 parameter reference pages: alkalinity, calcium, magnesium, salinity, pH, nitrate, phosphate, temperature. Each with measurement methods, target ranges, what's actually disagreed about, and inline citations.
• Added3 guides: starting a reef tank, two-part dosing explained, ideal reef parameters.
• AddedMethodology page documenting every constant on the site, traced to Randy Holmes-Farley, Bulk Reef Supply, Tropic Marin, Red Sea, or Triton.
• Added133 unit tests, all calculator math spot-checked against published reference values (e.g., Randy Recipe #1: 50 gal × 2 dKH = 71.15 mL ✓).