Disodium phosphate (sodium phosphate dibasic, anhydrous)
phosphate
Na2HPO4
Manufacturer data
As an Amazon Associate we earn from qualifying purchases. Buying through these links costs you nothing extra and helps keep the app free.
What one dose does
PARAMETER
1 g / 100 L
Phosphate
+6.69 ppm PO₄
To raise phosphate by 0.02 ppm PO₄ in 100 L: 0.003 g.
How it’s used
ACS/food grade; heptahydrate and dodecahydrate are common - check label.
Cautions
• 1 g in 100 L adds ~7 ppm PO4 (~70-230x a reef target of 0.03-0.1 ppm) - ALWAYS dose from a dilute stock.
• Only dose when PO4 is bottomed out (undetectable/<~0.02 ppm) with symptoms (pale corals, dinos/cyano under ULNS, carbon-dosing stall).
• Raise in small steps (<=~0.02-0.03 ppm per day, app policy) and re-test; overshoot fuels algae.
• Hydrate matters: anhydrous 66.9% PO4, heptahydrate 35.4%, dodecahydrate 26.5%.
pH effect: neutral at dose (mildly basic salt).
Sources
ACS/food grade; heptahydrate and dodecahydrate are common - check label.
pubchem.ncbi.nlm.nih.gov/