Demo Reef Log

Log a New Reading

Recent Readings

↑ Import CSV ↓ Download CSV

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

2026-09-21

—

78.4

8.22

—

340

✎

MANUAL

2026-09-20

8.2

422

1305

1.025

78.3

8.20

7.2

0.10

0.00

357

✎

MANUAL

2026-09-19

8.3

418

1313

1.025

78.3

8.22

7.3

0.10

0.00

357

✎

Preferred Ranges

Parameter	Target Range	Tolerable Range	Natural Ocean	Unit	Notes
Alkalinity dKH	8.0–12.0	7.0–13.0 dKH	7-8 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⁺	380–450	350–500 ppm	~400 ppm	ppm	🦴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⁺	1200–1400	1150–1450 ppm	~1285 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	1.023–1.026	1.022–1.028 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	76.0–80.0	74.0–82.0 °F	77-84°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.
pH	8.1–8.3	7.8–8.4	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⁻	2.0–10.0	1.0–30.0 ppm	~0.01-0.05 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. Aim for 5-10 ppm; above 30 ppm nuisance algae takes over.
Phosphate PO₄³⁻	0.03–0.1	0.01–0.2 ppm	~0.03 ppm	ppm	🎨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⁻	0.0–0.05	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