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, prep, purity, and dose ratios. Baked baking soda is soda ash, so the alkalinity chemistry is identical — the real differences are price and convenience.
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 @ 300 °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 | Raises pH (baked baking soda is soda ash) | Raises pH (same compound) |
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: Both stocks are soda ash. Any difference in mL per dKH comes from how much powder each recipe dissolves per gallon, not from the chemistry.
- pH effect of alk dose: Identical per dKH. Useful if your tank runs low; if it already runs high, dose unbaked baking soda (Randy Recipe #2) instead — bicarbonate barely moves pH.
- 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: Either works
Both alk sources are soda ash and raise pH by the same amount per dKH, which helps in CO₂-heavy rooms. Pick on cost (Randy) or convenience (BRS).
Tank pH already 8.2–8.4 and stable
Pick: Neither
Both recipes raise pH. Dose unbaked baking soda (Randy Recipe #2) for the alk side instead — sodium bicarbonate adds alkalinity with very little pH push.
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.
Which one should you buy?
Affiliate linksreefcalcs pick
Arm & Hammer Baking Soda — 13.5 lb
Nothing beats it on cost per dKH, and the bake step is a one-time hour in the oven at 300 °F. Baked, it is the same soda ash BRS sells. If your pH already runs high, skip the oven and dose it unbaked as bicarbonate (Randy Recipe #2).
~$10 · Where to buy →If you'd rather not bake
BRS Pharma Soda Ash (alkalinity component)
Pharma-grade soda ash — chemically identical to baked baking soda, so it raises pH just the same. You pay a little more to skip the oven and any question about what's in a grocery-store box.
~$25 · Where to buy →Needed for both recipes
BRS Pharma Calcium Chloride (Ca component)
Whichever alk source you pick, the calcium half is the same calcium chloride dihydrate both recipes are written around. Buy it once and dose against whichever recipe you settled on.
~$25 · Where to buy →Affiliate links. As an Amazon Associate, reefcalcs earns from qualifying purchases.
Also mentioned above
Affiliate links. As an Amazon Associate, reefcalcs earns from qualifying purchases.
Related calculators & references
Sources & references
- 1.Randy Holmes-Farley — A Homemade Two-Part Recipehttps://reefs.com/magazine/aquarium-chemistry-a-homemade-two-part-calcium-and-alkalinity-additive-system/
- 2.BRS — Two-Part Instructionshttps://www.bulkreefsupply.com/content/post/How-To-Dosing-Two-Part-in-Your-Reef-Tank
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