Dosing Elements
Magnesium reef supplement for stable Ca and Alk
Nereus Magnesium Supplement is a high-purity reef supplement (magnesium chloride) for keeping Mg in the reef aquarium sweet spot. Adequate magnesium helps calcium and alkalinity remain soluble, supports steady calcification, and reduces the ionic tug-of-war that shows up when Mg is ignored.
Many reefs deplete magnesium slowly through coral growth, salt mix variance and water changes. A dedicated magnesium reef supplement — dosed by hand or through a spare dosing channel — keeps the foundation under your two-part program.
Why reefers choose this reef supplement
- Supports long-term calcium and alkalinity stability
- Dissolves cleanly for manual or automated dosing
- Complements Nereus Alkalinity and Calcium reef supplements
- Practical for scheduled top-ups on mixed and SPS systems
- Clean, international-quality packaging for serious aquariums
How to use
- Test magnesium before adjusting — know your baseline.
- Dissolve the powder in RODI water per your preferred stock recipe until fully clear.
- Dose gradually toward your target range (many reefers aim roughly mid–high natural seawater Mg, adjusted to their salt and livestock).
- On systems with a third dosing head or spare pump, automate small maintenance additions; otherwise dose manually a few times per week.
- Re-test after changes settle, and keep Ca / Alk testing in the same routine.
Best practice
- Correct large Mg deficits slowly over several days, not in one heavy dose.
- Recheck calcium and alkalinity after major Mg adjustments — they often interact.
- Water changes with a quality salt mix reduce how aggressively you need to dose Mg.
- Store powder sealed and dry; label mixed solutions clearly.
Magnesium rarely gets the spotlight, but it quietly holds two-part reef chemistry together. Nereus Magnesium Supplement makes that maintenance straightforward and consistent.