Seachem Meridian 9kg

Seachem Meridian 9kg is a natural oolitic aragonite substrate for marine, reef and tropical aquariums. Oolitic means each grain is rounded, either spherical or egg-shaped, which gives a smooth sand bed that is comfortable for reef inhabitants. Being aragonite, it helps keep calcium and alkalinity steady and guards against sharp drops in pH, supporting more stable water chemistry over time. It needs only a quick rinse before going into the tank, and the fine, even grain gives a clean, natural look to the aquarium floor.

Key features of the Seachem Meridian 9kg

• Natural oolitic aragonite
• Rounded, smooth grains
• Helps stabilise calcium and alkalinity
• Buffers against pH drops
• For reef and marine tanks

Setting up

Rinse the sand briefly to wash off leftover dust. When filling the tank, stand a bowl on the substrate and pour water into it so it overflows gently and the bed is not disturbed. Some cloudiness at first is normal; filter floss or other mechanical filtration will clear it, and a clarifier such as Seachem Clarity can speed this up.

How much to buy

As a rough guide, dry aragonite weighs around 1.5kg per litre, so this 9kg bag gives about 6 litres of sand, enough for a layer of a little over 2cm across a 60 x 45cm tank floor. To work out your own needs, multiply the floor length by the width in centimetres and by the depth you want, then divide by 1,000 for litres. A shallow bed is easier to keep clean in a reef tank; stir or siphon the surface lightly during water changes so detritus does not build up.

Good to know

Test calcium and alkalinity regularly, as the substrate supports stable levels but does not replace dosing in a busy reef tank.

Seachem Meridian 9kg specifications

• Brand: Seachem
• Brand website: seachem.com
• Product: Seachem Meridian 9kg
• Weight: 9kg
• Type: Oolitic aragonite
• Grain size: 0.25-0.50mm
• Suitable for: Marine, reef and tropical aquariums
• Category: Fish Water Care