🚀 Use the live calculator · also at athena.legacy.ag
A precision dosing calculator for mixing Athena Pro Line nutrients into batch tanks of any size. Feed charts give you per-gallon ratios; this scales the official dosing chart to your exact reservoir — 17 gallons or 2,500 liters — with no manual math.
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Disclaimer: Independent tool — not affiliated with, endorsed, or sponsored by Athena. Verify all calculations. Use at your own risk.
- Official Athena dosing chart, interpolated — the chart anchors at EC 1.0 / 1.5 / 2.0 … 4.0; the calculator linearly interpolates between anchors so EC 2.7 gives a real dose instead of silently snapping to 2.5.
- Metric & Imperial — liters/gallons toggle. All rates are stored canonically (liters, ml/10 L) and converted only for display, so switching units never changes the actual dose.
- Growth-stage presets — Clone / Veg / Flower / Finish / Flush chips set pH, EC, Balance and Cleanse rates plus the usual product pair. Flush is RO + Cleanse only.
- Independent product toggles — Pro Grow, Pro Bloom, Pro Core and Pro Fade are each individually switchable with their own stock strength. Turning both A-parts (Grow + Bloom) or both B-parts (Core + Fade) on splits that part's chart dose 50/50 for transition feeds.
- Stack & IPM dosing — Stack as a drench additive (label: 1–2 ml/gal weekly, final veg week → flower week 3); IPM as a foliar spray-tank batch (60–90 ml/gal preventative, 90–120 active) with a hard warning that it never goes in the fertigation reservoir.
- Named recipes — save the entire form (stage, EC, products, strengths, Balance, Cleanse, Stack/IPM) under a name in the browser; load or delete with one tap.
- Pro Balance & Blended Balance — choose your pH buffer:
- Blended Balance (liquid potassium silicate) — ml dosing, label range 2–5 ml/gal.
- Pro Balance (dry potassium carbonate) — dose from a 40–120 g/L stock, with dry-gram equivalents shown.
- A dial-in utility converts "I used 73 ml to pH this tank" into a saved rate for next time. Rates are remembered per product.
- Athena Cleanse only — preset chips for Light / Maintenance / Reset / Flush rates (label: 2–5 ml/gal maintenance, 5–10 ml/gal reset & final flush). Anolyte support removed.
- Source water EC offset — running tap or bore water? Enter its EC and it's subtracted from the target before dosing (RO = 0).
- Mixed concentrate strengths — independent strength selectors for Grow/Bloom and Core/Fade stocks (113 / 226 / 240 / 282 g/L ⇄ 1 / 2 / 2.2 / 2.5 lb/gal), because real stockrooms have mismatched batches. Dry-gram equivalents shown for every dose.
- Top-up calculator — tank reads EC 2.4, target is 3.0? Get the exact ml of each part to add. Overshot? Get the liters of water to dilute with.
- Mix mode — fullscreen tank-side checklist in the correct order (Cleanse → Balance → Grow/Bloom → Core/Fade) with tap-to-tick steps and big numbers.
- History + CSV export — every calculation saved to localStorage, expandable entries, one-tap delete, CSV export. Old-version history is migrated automatically.
- Share — native share sheet on mobile, clipboard fallback on desktop.
- Phone-first — big touch targets, no-zoom inputs, safe-area aware, works as a home-screen app. Single file, no backend, no accounts, fully offline once saved locally.
The calculator is a single self-contained HTML file designed to drop into any site:
<iframe src="https://jaketherabbit.github.io/Athena-Batch-Tank-Nutrient-Calculator/?embed=1"
style="width:100%;border:0" id="athena-calc"></iframe>
<script>
addEventListener('message', e => {
if (e.data?.type === 'abt-height')
document.getElementById('athena-calc').style.height = e.data.height + 'px';
});
</script>?embed=1 hides the header/footer chrome, and the page posts its height to the parent on every resize for seamless auto-sizing.
No installation, no build. Download www/index.html and open it in any modern browser — everything runs client-side. On a phone, use the browser's Add to Home Screen for an app-like fullscreen experience.
- Pick a growth stage — pH, EC, Balance and Cleanse rates pre-fill (everything stays editable).
- Set target EC with the slider and enter your tank size.
- Pick the concentrate strength each stock was mixed at — Grow/Bloom and Core/Fade can differ.
- Choose your Balance product and rate (use the dial-in utility to capture your water's real demand).
- Calculate → doses appear with per-10 L (or per-gal) rates and dry-gram equivalents.
- Hit Mix mode at the tank and tick off each addition as you pour.
The dose tables are Athena's published dosing chart, taken verbatim. Doses between chart anchors are linear interpolations; an EC below 1.0 is flagged as extrapolated.
www/index.html— the app (single file: HTML + CSS + vanilla JS, zero dependencies).docs/index.html— identical copy served by GitHub Pages. Keep both in sync when editing.
Bug reports and PRs welcome. For major changes, open an issue first.
MIT