#pH

pH is the noisiest parameter on a reef tank — it swings on a day-night cycle, climbs when the lights come on, and drops when CO2 builds up. Most reef tanks stabilize in the 7.9 to 8.4 range over 24 hours. Reef Trak can pull continuous pH from Apex Fusion or HYDROS controllers and show the full curve, not just a single reading.

Articles tagged pH

Reef Chemistry · February 28, 2026

Why Reef Tank pH Drops at Night (And How to Fix It)

Almost every reef tank shows lower pH at night than during the day. It is normal biology and indoor air CO2. Here is exactly why and what to do about it.

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Reef Chemistry · February 5, 2026

Reef Tank pH: Target Range, Why It Drops at Night, and How to Stabilize It

pH is the most rhythmic parameter in a reef tank. It rises during the day and drops at night, and indoor CO2 is the #1 reason a tank runs low. Here is the practical guide.

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