Looking into a parameter
A widget shows you a number. Tapping it shows you the story behind the number.
What you get
A history chart, with its own range selector: 1h · 6h · 12h · 24h · 3d · 7d and longer.
A source filter. Below the ranges is a row of chips: All, plus one per source reporting this parameter, such as Apex, Cora, Red Sea™ or Manual. Select one to see only its readings. This is how you compare a probe against a test kit directly: switch between them on the same chart.
A dose calculator link, for parameters you dose. It uses the tank volume from your tank profile and the strengths from Dosing.
A comparison overlay. Compare with draws a second parameter on the same chart (alkalinity against calcium, pH against temperature), so a relationship you suspect becomes visible instead of remembered.
Summary statistics for the window on screen: MIN, AVG and MAX, shown as a row under the current value.
Dose markers on the chart, so a movement can be lined up against what you actually dosed.
The raw readings list: every individual reading behind the line, with its source and timestamp.
Your alert band, shaded on the chart, so a reading is read against its range rather than in isolation. To change the range itself, long-press the widget on the dashboard. See Alerts and thresholds.
Log a reading by hand.
Choosing a range
The right range depends on the rhythm of the parameter:
| Parameter | Useful window |
|---|---|
| pH | 24 hours; it swings on a daily cycle |
| Temperature | 24 hours or 7 days |
| Alkalinity | 7 or 30 days |
| Trace elements | 30 days or a year |
Comparing sources
When more than one source reports a parameter, Cora keeps them separate rather than averaging them. Use the source chips to view each in turn.
A persistent offset between a probe and a hand-logged test usually indicates the probe needs calibrating.
An ICP result is a useful third opinion, but not an arbiter. Laboratories differ from one another, and the sample's handling, storage and transit all move the result. Treat a single ICP as evidence, not as the true value; two tests agreeing is worth far more than one.
Choosing which source a widget trusts
If you want a widget to follow one particular source, set that in the widget's settings. See Editing your dashboard.
Excluding a bad reading
A probe that spiked, a test misread, a sample taken mid water-change: a single wrong reading distorts the chart, the averages and anything reasoning from them.
Open the readings list from the icon in the top bar, then tap a reading to exclude it. The screen says it plainly: excluded from averages and insights, but it stays in your log. Nothing is deleted, and it can be restored.
Recording probe care
Logging a calibration or cleaning from here stamps the date against that source, so a later disagreement can be read against when the probe was last seen to. See Probes.
Logging a reading by hand
Enter what your test kit says. Hand-logged readings are first-class: they get their own source and timestamp, they appear on the chart, they feed Reef Buddy, and they are what Cora compares your equipment against.
Written for Cora Max 0.28.60 and Cora Mobile 0.5.70. Last checked 2026-09-09.
Still stuck? Email cora@coraiq.tech and we'll help.