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Logging for: 2026-06-29
Fields pre-filled from your last reading — adjust any that have changed.
8.0–12.0 dKH
380–450 ppm
1200–1400 ppm
1.025–1.026 sg
75.9–80.0 °F
8.1–8.4
1.0–10.0 ppm
0.01–0.03 ppm
0.0–0.1 ppm
0.0–0.02 ppm
250.0–400.0 mV
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DatedKH
dKH
Ca²⁺
ppm
Mg²⁺
ppm
Sal
sg
Temp APEX
°F
pH APEXNO₃⁻
ppm
PO₄³⁻
ppm
NO₂⁻
ppm
NH₃
ppm
ORP APEX
mV
APEX
2026-06-29
78.48.22340
MANUAL
2026-06-28
8.341613161.02578.38.227.10.100.00.00359
MANUAL
2026-06-27
8.342113141.02578.18.207.40.100.00.00358
Preferred Ranges
ParameterTarget RangeTolerable RangeNatural OceanUnitNotes
Alkalinity
dKH
8.0–12.07.0–13.0 dKH7-8 dKHdKH🧪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⁺
380–450350–500 ppm~400 ppmppm🦴Calcium is literally what coral skeletons are made of. 420-440 ppm is the sweet spot — not too low (slow growth) or too high (chemistry gets weird).
Magnesium
Mg²⁺
1200–14001150–1450 ppm~1285 ppmppm🔗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.
Salinity1.025–1.0261.022–1.028 sg1.025-1.027sg🧂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.
Temperature75.9–80.074.0–82.0 °F77-84°F°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.
pH8.1–8.47.8–8.4 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⁻
1.0–10.01.0–20.0 ppm~1-5 ppmppm🌿A little nitrate is actually good — corals and algae need it as food. The danger zone is above 20 ppm where nuisance algae explodes. Aim for 5-10 ppm.
Phosphate
PO₄³⁻
0.01–0.030.01–0.1 ppm~0.03 ppmppm🎨Corals need tiny amounts of phosphate to look colorful. Zero phosphate = pale, stressed corals. Too much = algae takeover. 0.05-0.08 ppm is the sweet spot.
Nitrite
NO₂⁻
0.0–0.10.0–0.5 ppm~0 ppmppm⚠️Nitrite is the middle step in the nitrogen cycle — toxic to fish gills. Should be zero in an established tank. If it spikes, something died or your cycle isn't done.
Ammonia
NH₃
0.0–0.020.0–0.1 ppm~0 ppmppm☠️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.
ORP250.0–400.0200–450 mV~400 mVmVOxidation 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