Seachem Reef Builder Reef Aquarium Alkalinity Supplement, 600 g, Low pH Impact

Seachem Reef Builder is a reef aquarium supplement for raising carbonate alkalinity (KH), supplied in a 600 g (1.3 lb) container.

• Raises carbonate alkalinity with minimal impact on pH — adjust KH without immediately shifting pH.
• Uses a blend of carbonate sources — unlike bicarbonate-only products, it will not lower pH.
• When used as directed, does not deplete calcium, magnesium or strontium — these minerals can precipitate as alkalinity rises.
• Long-term use tends toward pH 8.3 — a stated outcome of ongoing use.
• Reef Builder and Reef Buffer have different roles — use Reef Builder for KH without raising pH, or Reef Buffer to raise KH and pH.
• Carbonates and calcium are essential to coral growth — deficiencies can stop growth and be followed by a rapid decline in coral health.

Maintaining carbonate alkalinity is part of supporting a reef aquarium where corals rely on both carbonates and calcium for growth. Reef Builder is made for aquarists who want to raise KH while keeping the immediate effect on pH low. It focuses on alkalinity rather than serving as a product for raising both alkalinity and pH.

Does Reef Builder raise carbonate alkalinity without raising pH?

Yes. Seachem Reef Builder raises carbonate alkalinity with minimal immediate impact on pH. Its blend of carbonate sources is formulated not to lower pH, unlike bicarbonate-only products that can have that effect. With long-term use, pH tends to stabilize at 8.3.

• Intended parameter: carbonate alkalinity (KH).
• Use it when the goal is to raise KH without raising pH.

Why does carbonate alkalinity matter for coral growth?

Carbonates and calcium are essential to coral growth. When either becomes deficient, coral growth can cease, followed by a rapid decline in coral health. Reef Builder raises carbonate alkalinity; the product’s stated use as directed will not deplete calcium, magnesium or strontium, minerals that can precipitate as alkalinity increases.

• Use as directed to maintain the product’s stated mineral balance.
• Reef Builder addresses carbonate alkalinity; it is not presented as a calcium supplement.

How is Reef Builder different from Reef Buffer?

Seachem Reef Builder raises carbonate alkalinity without affecting pH, while Reef Buffer raises both carbonate alkalinity and pH. The two products may be used together, with each serving its stated role in adjusting these aquarium parameters.

• Reef Builder: raise carbonate alkalinity without affecting pH.
• Reef Buffer: raise carbonate alkalinity and pH.

Seachem Reef Builder suits reef aquarists seeking to raise carbonate alkalinity while limiting immediate pH impact, particularly when maintaining the carbonate availability corals need for growth. It is a KH-focused supplement rather than the option for raising pH at the same time. Its purpose is to adjust carbonate alkalinity, with Reef Buffer serving the combined KH-and-pH role.