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Coralkinhonest saltwater & reef care · coralkin.comReef Parameter Cheat-Sheet
🌡️ Target parameters (mixed reef)
- Salinity
- 33–35 ppt (SG ≈1.0264 at 25 °C)
- Temperature
- 76–82 °F (24.5–27.8 °C) — stable
- pH
- 8.1–8.4
- Alkalinity
- 8–11 dKH (SPS often 7–8) — kept STABLE
- Calcium
- 400–450 ppm
- Magnesium
- 1300–1400 ppm
- Nitrate (NO₃)
- 2–15 ppm — low, but NOT zero
- Phosphate (PO₄)
- 0.03–0.10 ppm — low, but NOT zero
- Ammonia (NH₃)
- 0 — undetectable
- Nitrite (NO₂)
- 0 — undetectable
Targets suit a mixed reef; SPS-dominant tanks run tighter (see notes on the full chart).
✅ Golden rules (every reef)
- STABILITY beats hitting an exact number — a steady tank is a healthy tank, especially for alkalinity.
- Test, don’t guess. Keep a refractometer (not a swing-arm hydrometer) and reef test kits, and check before you change anything.
- Nitrate and phosphate should be LOW, not zero — corals feed on them, and zero invites dinoflagellates.
- Ammonia and nitrite are the only things that should read zero — that’s a cycled tank.
- Top up evaporation with fresh RO/DI (0 TDS), never saltwater — salinity rises as water evaporates.
- Change water with salt mixed to the SAME salinity and temperature as the tank.
- Don’t dose calcium and alkalinity at the same point — they precipitate; dose apart, into flow.
- When something looks off, test the water first — then ask. Most reef problems are water problems. 💧