Comparison
Randy Recipe #1 vs BRS Two-Part
Randy Holmes-Farley's Recipe #1 (baked baking soda + CaCl₂) vs BRS's two-part (soda ash + CaCl₂) compared on cost, pH side effects, mixing complexity, and dose ratios. Both are stoichiometrically balanced — but they're not interchangeable.
The contenders
Side A
Randy Recipe #1
Baked NaHCO₃ + CaCl₂
Side B
BRS Two-Part
Na₂CO₃ (soda ash) + CaCl₂
Spec-by-spec
| Spec | Randy Recipe #1 | BRS Two-Part |
|---|---|---|
Alk component source | Baked baking soda (NaHCO₃ → Na₂CO₃) | Soda ash (Na₂CO₃) |
Calcium component | CaCl₂·2H₂O (dihydrate) | CaCl₂·2H₂O (dihydrate) |
Bake step required? source | Yes — 1 hour @ 250 °F before mixing | No — pre-converted |
Stock solution (Alk) source | 594 g baked NaHCO₃ / US gal | Per BRS calculator |
Stock solution (Ca) | 500 g CaCl₂·2H₂O / US gal | Per BRS calculator |
Dose for +1 dKH per gal source | ~0.711 mL | Equivalent (different unit math) |
pH effect of alk dose | Mild (pH-neutral when baked properly) | Raises pH (soda ash is more basic) |
Cost (alk side) | ~$0.02 per dKH per 100 gal (Arm & Hammer) | Higher (BRS sells the bag) |
- Bake step required?: BRS skips the oven step.
- Dose for +1 dKH per gal: BRS dose differs because soda ash is more concentrated than baking soda by mass.
- pH effect of alk dose: Soda ash pushes pH up — useful if your tank runs low, problematic if you're already high.
- Cost (alk side): Baked baking soda from any grocery store is cheaper than BRS soda ash.
Which one for which situation
Tank pH chronically low (<7.9) due to high CO₂
Pick: BRS Two-Part
Soda ash raises pH, which helps in CO₂-saturated rooms. Randy's baked version is pH-neutral.
Tank pH already 8.2–8.4 and stable
Pick: Randy Recipe #1
You want the pH-neutral dose. Soda ash will push you into the 8.4+ zone unnecessarily.
Minimum-cost dosing on a large tank
Pick: Randy Recipe #1
Arm & Hammer baking soda is the cheapest alk source on the market. The bake step is annoying once, then trivial.
Beginner who doesn't want to bake
Pick: BRS Two-Part
Soda ash skips the oven step entirely. The cost penalty is real but not enormous.
Either: you own a dosing pump and just want the cheaper recipe
Pick: Randy Recipe #1
Same math, same balance, lower cost. The bake is a one-time prep task.
Where to buy
Randy Recipe #1
Arm & Hammer Baking Soda — 13.5 lb
Bake at 250°F for 1 hour to convert to soda ash. Cheapest alk source.
View on Amazon →
BRS Pharma Calcium Chloride (Ca component)
Anhydrous CaCl₂ for two-part dosing. Use Randy's recipe math.
View on Amazon →
BRS Two-Part
BRS Pharma Sodium Bicarbonate (alkalinity component)
Pre-baked NaHCO₃ for Randy/BRS two-part. Skip the oven step.
View on Amazon →
BRS Pharma Calcium Chloride (Ca component)
Anhydrous CaCl₂ for two-part dosing. Use Randy's recipe math.
View on Amazon →
ESV B-Ionic Two-Part
Pre-mixed liquid two-part if you don't want to DIY.
View on Amazon →
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Related calculators & references
Sources & references
- 01Randy Holmes-Farley — A Homemade Two-Part Recipehttps://reefs.com/magazine/aquarium-chemistry-a-homemade-two-part-calcium-and-alkalinity-additive-system/
- 02BRS — Two-Part Instructionshttps://www.bulkreefsupply.com/content/post/brs-two-part-instructions
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