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BRS Calculator Alternative — alkalinity, calcium, magnesium dosing

BRS has run the original reef calculator at bulkreefsupply.com/calculators/reef-calculator for years. It works. It also (a) gates a few products behind your account email, (b) doesn't link out to the underlying chemistry, and (c) only exposes BRS-branded chemistry. This page is the alternative — same outputs, sourced inline, with Tropic Marin and Red Sea added.

Alkalinity dosing

Required change
1.50dKH
Liquid dose
53.50mL

Mix 1½ cups BRS Pharma soda ash per 1 US gal RO/DI. Published reference: ~107 mL of stock raises a 100-gal system by 1.5 dKH.

Source: www.bulkreefsupply.com

How this is calculated

What this calculator does

The default selection is BRS Pharma Soda Ash — same recipe as BRS's mixing instructions page. Pick a different product in the dropdown for Randy Recipe 1 / 2, Tropic Marin All-For-Reef, Red Sea Foundation B, or Triton Base 1. The math is identical for every product — only the constant (dKH per mL per gallon) changes.

Why an alternative?

  • No account required. Some BRS calculators ask you to sign in; this one never will.
  • All recipes side by side. Switch Randy ↔ BRS ↔ Tropic Marin ↔ Red Sea in one dropdown to compare doses for the same parameter change.
  • Sourced inline. Every constant in this calculator links back to the manufacturer instructions or the Reefkeeping article it came from.
  • Mobile-friendly. The original BRS calculator is desktop-first; this one renders properly on phones.

Full set of dosing calculators

FAQ

Is this the BRS reef calculator?
No — it's an independent alternative. We implement the same Randy Holmes-Farley recipes that the BRS calculator uses, plus the BRS Pharma products with constants from the BRS mixing instructions pages. No affiliation with Bulk Reef Supply.
Does it match BRS's calculator numbers?
Yes for Randy Recipe 1 and BRS Pharma — same recipe constants. The Tropic Marin and Red Sea products use those manufacturers' own published per-day dose caps and ppm-per-mL ratios, so those are sourced separately.
Why does the dose differ between Randy and BRS soda ash?
Same chemical (sodium carbonate, Na₂CO₃), same concentration when mixed at the standard ratio. Doses match. Differences only show up at half-strength stocks or if you've baked your own baking soda incompletely.
Where do I get the chemicals?
Bulk Reef Supply, Amazon (search 'pharmaceutical grade calcium chloride'), or any food-grade pickling supplier for the calcium chloride. For Tropic Marin and Red Sea, buy direct from the manufacturer or licensed reseller — the prepackaged kits are convenient but cost 4–6× the cost per dKH of bulk powders.
Do I need separate calcium and alkalinity calculators?
Yes — they're two different chemistries delivered from two different bottles. Use the alkalinity one to size the daily Part 2 dose and the calcium one to size the Part 1 dose. Two-part means equal-volume dosing to keep the molar ratio balanced.
Share / embed this calculator

Paste this snippet into any blog or forum post that allows raw HTML to embed the calculator.

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  width="100%"
  height="720"
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  loading="lazy"
  title="ReefCalcs BRS Calculator Alternative — alkalinity, calcium, magnesium dosing"
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Sources & references

  1. 01
    Bulk Reef Supply — Reef Calculator (the original)
    https://www.bulkreefsupply.com/calculators/reef-calculator
  2. 02
    BRS Pharma Soda Ash mixing instructions
    https://www.bulkreefsupply.com/content/post/brs-pharma-soda-ash-mixing-and-dosing-instructions
  3. 03
    BRS Pharma Calcium Chloride mixing instructions
    https://www.bulkreefsupply.com/content/post/brs-pharma-calcium-chloride-mixing-and-dosing-instructions
  4. 04
    Randy Holmes-Farley — Recipe 1 (Reefs.com)
    https://reefs.com/magazine/aquarium-chemistry-a-homemade-two-part-calcium-and-alkalinity-additive-system/

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