Low Magnesium in Reef Tanks: Why It Matters and How to Raise It

Low magnesium in a reef tank

Magnesium plays a big role in keeping alkalinity and calcium behaviour predictable. Keeping it stable helps the whole system.

Common signs

Hard to stabilise alkalinity
Magnesium tests trending down
Unpredictable parameter swings

Common causes

High uptake in growing systems
Infrequent testing
Inconsistent supplementation

A safe plan that actually works

Confirm the reading, then correct gradually.
Re-test after adjustments and avoid big jumps.
Lock in a routine that matches consumption.

Recommended product: Magnesium+ (with Trace)

Raises magnesium in a controlled way
Supports stable overall chemistry
Complements alkalinity and calcium routines

Shop Magnesium+

Explore Collection

We deliver premium live foods, high quality reef chemistry products, and more across Australia, including major cities, outer suburbs, rural areas, and everywhere in between (even if your location is not listed). QLD (Brisbane, Gold Coast, Sunshine Coast, Townsville, Cairns, Toowoomba, Rockhampton, Mackay, Bundaberg), NSW (Sydney, Newcastle, Wollongong, Coffs Harbour, Port Macquarie), VIC (Melbourne, Geelong, Ballarat, Bendigo, Mildura), WA (Perth, Bunbury, Geraldton, Albany, Kalgoorlie Boulder), SA (Adelaide), TAS (Hobart, Launceston), ACT (Canberra), NT (Darwin), NSW/VIC (Albury Wodonga).

Low Magnesium in Reef Tanks: Why It Matters and How to Raise It

Low magnesium in a reef tank

Common signs

Common causes

A safe plan that actually works

Recommended product: Magnesium+ (with Trace)

Quick links

Tools

Stay updated

Visiting from the United States?

Shopping Cart

Item added to your cart

Your cart is empty

Subtotal

Add a note to your order

Estimate shipping rates