Mg Plus 250 ml — Concentrated Liquid Magnesium for Reef Aquariums - Aquaforest

Aquaforest Mg Plus 250 ml — fast magnesium solution for reef aquariums

The Mg Plus 250 ml delivers ionic magnesium in a liquid ready-to-dose solution. Used to lift a falling magnesium, correct a moderate deficit, or hold Mg at target on a Ca+ / KH+ / Mg+ managed tank. Its moderate concentration makes it easy to tune without risking the big swings that a heavy dose would cause.

The 250 ml format suits reef tanks up to 200 L in moderate dosing. Aquaforest recommends holding Mg between 1,180 and 1,460 ppm to preserve Ca/Mg ratio stability and prevent abiotic calcium carbonate precipitation.

When to use Mg Plus

• Mg drop below 1,180 ppm — gradual return to 1,300-1,400.
• Add-on to separate Ca dosing — Ca+ / KH+ / Mg+ method.
• Nano reef with moderate consumption — no need for full Balling.
• Correction after ICP flagging a Mg deficit.

Aquaforest official dosing

• Starting dose: 5 ml per 100 L of tank water per day.
• Measurable effect: 10 ml in 100 L raises Mg by 10 ppm.
• Maximum dose: 100 ml per 100 L per day — very wide ceiling.
• Max rate: do not raise Mg by more than 100 ppm per 24 h.
• Tuning: in 5-10 ppm target steps, week over week.

Specifications

• Brand: Aquaforest (Poland)
• Format: 250 ml bottle
• Type: standard liquid magnesium solution
• Compatibility: nano and small-to-mid reef tanks, all coral types

Why choose Aquaforest at ReefSolution

• Lab Mg Plus 2 L — the large format for established tanks and steady consumption.
• Ca Plus 250 ml — the calcium to dose alongside.
• Magnesium Test Pro — the essential Mg test to fine-tune the dose.

Frequently asked questions

Why is the Mg Plus daily ceiling so wide?

Magnesium is the least sensitive parameter to rapid swings — a 50-100 ppm spike over 24 h triggers neither osmotic shock nor precipitation. Aquaforest can therefore allow a 100 ml/100 L/day ceiling, far above KH Plus (10 ml) or Ca Plus (20 ml). That makes a fast recovery possible on very low Mg without immediate risk.

How long does a 250 ml bottle last on a 100 L tank?

At the 5 ml/day starting dose, a 250 ml bottle covers 50 days (about 1.7 months). Under heavier dosing (20-30 ml/day for fast correction), it lasts just 8-12 days.

Should I test Mg monthly?

On a stable tank in Ca+/KH+/Mg+ or Balling mode, a monthly Mg check is enough. On a tank just starting dosing or after a salt change, twice-weekly tests help dial in the right dose.