All about Fishy!

Choosing the right substrate for a saltwater reef tank is more than just picking what looks nice—it’s about creating a healthy environment for your corals, fish, and beneficial bacteria. Two popular options from Seachem—Meridian and Pearl Beach—are both made from natural aragonite and designed to help maintain stable water chemistry. Here’s what you need to know to choose the one that’s right for your aquarium.

1. What Is Aragonite Sand & Why It Matters

Aragonite is a natural form of calcium carbonate that helps buffer pH and adds essential minerals like calcium and carbonate to your tank water. This is especially important in reef tanks, where stable parameters are key for coral growth and overall tank health.

2. Seachem Meridian: The Oolitic Luxury

• Composition & Benefits

  • A natural oolitic (spherical or egg-shaped) aragonite substrate.

  • Grain size is fairly uniform at 0.25–0.50 mm, optimal for reef inhabitants.

  • Assists in stabilizing calcium and alkalinity, and helps prevent large pH declines.

  • Dry-packed, so you're paying only for the gravel—no water weight inflated like in “wet” substrates.

• Mineral Analysis (ppm):

  • Ca: 347,750

  • Fe: 44.2

  • Mg: 1,845

  • Mn: 2.6

  • Mo: 2.35

  • Sr: 8,420

  • V: 8.1

  • Zn: 4.75.

• Setup Tips

  1. Rinse thoroughly to remove dust. No need to make the sand clear, 1-2 rinse is enough.

  2. Fill the tank slowly using a bowl to reduce disturbance to the sand bed.

  3. Expect initial cloudiness—remove it via mechanical filtration or Seachem’s Clarity.

3. Seachem Pearl Beach: The Natural Choice

• Composition & Benefits

  • All-natural aragonite substrate for marine, reef, and tropical tanks.

  • Like Meridian, it stabilizes calcium and alkalinity while preventing major pH shifts.

  • Dry-packed, delivering 35% more gravel by volume than equivalent weight “wet” gravels.

• Mineral Analysis (ppm):

  • Ca: 376,041

  • Fe: 1,102

  • Mg: 248

  • Mn: 7

  • Mo: 2

  • Sr: 1,241

  • V: 15

  • Zn: 2.

• Setup Tips
  Follow the same steps as with Meridian: rinse, fill slowly, and filter out cloudiness using mechanical means or Seachem Clarity.

4. Side-by-Side Comparison

5. Which One Should You Pick?

• Choose Meridian if you want very consistent grain texture that reef critters like gobies and sand sifters will appreciate. Its buffering is solid, and the mineral profile supports stability.

• Choose Pearl Beach if you're aiming for a more natural grain variance and slightly higher calcium buffering—plus, you get more sand for your money.

6. Pro Setup Practices

1. Rinse thoroughly to eliminate dust.

2. Slow-fill using a bowl to preserve substrate clarity.

3. Use mechanical filtration or Seachem Clarity to clear initial clouding.

4. Monitor water parameters in the first weeks, as there may be gradual buffering effects.