Marine Buffer 500 g — Buffer pH 8.3 with Borates Seawater | Seachem

Seachem Marine Buffer in a 500g format is a multi-component powder buffer designed to raise and stabilize the pH at 8.3 in all saltwater aquariums. Its unique formulation prevents the pH from exceeding 8.3, even in the event of an accidental overdose, unlike simple sodium bicarbonate or sodium carbonate which can raise the pH to dangerous levels. Marine Buffer contains sodium, magnesium, calcium, strontium, and potassium salts in the form of carbonates, bicarbonates, chlorides, sulfates, and borates. The 500g format is suitable for medium-sized marine aquariums requiring regular pH maintenance.

Main advantages

• Stabilizes the pH at 8.3 — impossible to exceed this level even in case of overdose
• Contains borates for increased buffer system stability — the first buffer on the market to incorporate borate salts
• Contains magnesium to mitigate the effects of precipitation
• Multi-salt mixture (Na, Mg, Ca, Sr, K) — superior to simple sodium bicarbonate
• Economical 500g format for regular maintenance

Use in marine aquariums

Total alkalinity relies on three main ions: carbonate (raising the pH to around 9.1), bicarbonate (around 7.8), and borate (around 9.5). Marine Buffer combines these elements to target a stable pH of 8.3. Most marine salts contain significant amounts of bicarbonates, which lower the pK of the buffer system. Marine Buffer compensates for this influence with a pK slightly above 8.3. It is safe for use in reef aquariums, and its effectiveness improves with continued use.

Dosage

• 5 g (1 level teaspoon) per 80 L (20 US gallons). Each dose increases alkalinity by 1 meq/L.
• Dissolve in at least 250 ml (1 cup) of fresh water before adding to the tank.
• Add daily until the pH stabilizes at 8.3 — from 1 day to 1 week depending on the original pH and alkalinity.
• Then, use every 2 weeks to once a month to maintain a pH of 8.3.

Precipitation diagnosis

In ionically balanced seawater, the Marine Buffer produces little precipitation or turbidity. If a significant precipitate forms and does not dissolve within 15 minutes, the water has an ionic imbalance requiring a water change before continued use. A slight, white, flaky precipitate is temporary magnesium carbonate that redissolves within 30 minutes; this is often observed when magnesium levels are high.

Manufacturer's precautions

• Do not mix directly with a calcium, magnesium or strontium supplement.
• If regular dosing is not enough to maintain the pH, check overcrowding, overfeeding, or other management practices as a likely cause.
• Effectiveness improves with continued use

Available formats

• 50 g
• 250 g
• 500 g
• 1 kg
• 4 kg

Why choose the Marine Buffer from ReefSolution?

The Marine Buffer is the ideal choice for stabilizing the pH of marine fish tanks and reef systems. For reef tanks with a high organic load requiring a more aggressive buffer, consider the Seachem Reef Buffer (pK 8.6). Supplement with Seachem Marine Trace for trace elements and monitor your parameters with the Salifert KH/Alk Test Kit or the Hanna Checker Alkalinity.

Frequently Asked Questions

Can the Marine Buffer be used in a reef aquarium?

Yes, the Marine Buffer is safe for reef tanks. However, for reef systems with a high organic load where the pH regularly drops below 8.2, the Seachem Reef Buffer, with its pK of 8.6, will be more effective at achieving a stable pH of 8.3.

Can the Marine Buffer raise the pH above 8.3?

No. The multi-salt formulation of Marine Buffer prevents the pH from exceeding 8.3 even in the event of an accidental overdose, unlike simple bicarbonate or sodium carbonate which can raise the pH to dangerous levels.

A white precipitate forms after the titration — is this normal?

A light, white, flaky precipitate is temporary magnesium carbonate that redissolves within 30 minutes, often seen when magnesium levels are high. A large precipitate persisting for more than 15 minutes indicates an ionic imbalance—perform a water change before continuing.