Demo Reef Log
Edit Reading — 2026-09-28
Recent Readings
| Date | dKH dKH | Ca²⁺ ppm | Mg²⁺ ppm | Sal sg | Temp APEX °F | pH APEX | NO₃⁻ ppm | PO₄³⁻ ppm | NO₂⁻ ppm | NH₃ ppm | ORP APEX mV | |||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
APEX 2026-09-28 | 8.30 | 420 | 1310 | 1.025 | 78.4 | 8.22 | 8.0 | 0.11 | 0.00 | 0.00 | 340 | ✎ | ||||||||
Temperature78.4–78.4 °F Δ0.0 pH8.22–8.22 Δ0.00 ORP340–340 mV Δ0
| ||||||||||||||||||||
MANUAL 2026-09-27 | 8.30 | 417 | 1310 | 1.025 | 78.1 | 8.20 | 7.6 | 0.10 | 0.00 | 0.00 | 359 | ✎ | ||||||||
MANUAL 2026-09-26 | 8.20 | 418 | 1314 | 1.025 | 78.3 | 8.21 | 7.7 | 0.10 | 0.00 | 0.00 | 363 | ✎ | ||||||||
Preferred Ranges
| Parameter | Target Range | Tolerable Range | Natural Ocean | Unit | Notes |
|---|---|---|---|---|---|
| Alkalinity dKH | 7.0–11.0 | 6.0–12.0 dKH | ~6.5 dKH | dKH | 🧪This is the #1 parameter that kills corals when it swings. Think of it as the skeleton-building ingredient. Dose consistently and test every day if you have SPS. |
| Calcium Ca²⁺ | 400–550 | 370–600 ppm | ~420 ppm | ppm | 🦴Calcium is literally what coral skeletons are made of. Randy Holmes-Farley's range is 400-550 ppm, and natural seawater sits around 420. Low calcium slows growth; far above the range, the chemistry gets harder to keep balanced. |
| Magnesium Mg²⁺ | 1250–1400 | 1200–1450 ppm | ~1280 ppm | ppm | 🔗Magnesium is the chemistry glue — it keeps calcium and alkalinity from fighting each other. Low mag = parameters that won't stay stable no matter what you dose. |
| Salinity | 1.025–1.027 | 1.023–1.028 sg | 1.025-1.027 | sg | 🧂Match the real ocean exactly — 1.025 SG. Your fish evolved for this. Even small swings stress them out. An ATO keeps it rock steady. |
| Temperature | 76.0–82.0 | 74.0–84.0 °F | variable | °F | 🌡️Keep it like a warm beach day — 78°F is the sweet spot. Too cold and fish get sluggish. Too hot and oxygen drops fast. |
| pH | 7.8–8.55 | 7.6–8.65 | 8.0-8.3 | ⚗️The ocean is slightly basic, and your tank should be too. pH naturally drops at night — open a window or run a refugium on a reverse cycle to keep it up. | |
| Nitrate NO₃⁻ | 5.0–50.0 | 1.0–100.0 ppm | <0.1 ppm | ppm | 🌿A little nitrate is actually good — corals need it as food. Zero is a problem, not a win: it starves corals of color and, when phosphate stays up, invites dinoflagellates. Randy Holmes-Farley lets it float between 5 and 50 ppm, and warns that more problems come from lowering nitrate than from the level itself. Steady beats low. |
| Phosphate PO₄³⁻ | 0.06–0.3 | 0.02–0.5 ppm | ~0.005 ppm | ppm | 🎨Corals need tiny amounts of phosphate to look colorful. Zero phosphate = pale, stressed corals. Randy Holmes-Farley lets it float between about 0.06 and 0.3 ppm. Above that, bring it down slowly, over weeks, not days. |
| Nitrite NO₂⁻ | 0.0–0.2 | 0.0–0.5 ppm | ~0 ppm | ppm | ⚠️Nitrite is the middle step in the nitrogen cycle. In saltwater it's far less dangerous than in freshwater — seawater's chloride blocks it at the gill — so treat it as a cycling telltale, not a toxin. A trace reading is usually test-kit noise. A real, sustained rise means your cycle isn't finished or something died. |
| Ammonia NH₃ | 0.0–0.0 | 0.0–0.1 ppm | ~0 ppm | ppm | ☠️The most dangerous parameter. Even 0.25 ppm can kill fish within hours. Zero always. If you see any ammonia in an established tank, do a water change immediately. |
| ORP | 250–400 | 200–450 mV | ~400 mV | mV | ⚡Oxidation reduction potential — a real-time proxy for water cleanliness. Healthy reef tanks sit 250–400 mV; lower hints at organic load building up (skimmer, GAC, water change). Probe drift is common; recalibrate quarterly. |
Target ranges reflect your settings; “Natural Ocean” is the reference seawater value. Customize in Settings
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