Frequently asked questions

Short answers here, with links to the full pages. If your question is really "something looks wrong", go straight to Troubleshooting.

Getting started

What do I need to buy to use Cora?

Just a phone. Cora Mobile runs your tanks, devices and alerts on its own. Cora Max is an optional wall screen for the reef room. More in Cora Help.

Do I need a Cora Max, or can I use just the phone app?

The phone app is enough. Every core feature (tanks, devices, dashboards, alerts, dosing) is in Cora Mobile. Cora Max shows the same tanks on a bigger screen and adds voice. See Cora Help and Setting up Cora Mobile.

How do I add my first tank?

Cora Mobile walks you through it. Create your account, add a tank, and answer its profile questions. Devices and dashboards come after that. More in Setting up Cora Mobile.

What does "tank profile" mean and why does it ask so many questions?

The tank profile describes your system: size, water type, livestock, and how you dose and test. Cora uses your answers to set sensible starting thresholds, and to make Reef Buddy and Cora Assistant talk about your tank instead of reefs in general. More in Tank profile.

How long does setup take?

One tank with no equipment takes a few minutes. Each real device (probe, controller, pump) needs its own pairing step, so that part takes longer. You can always add more later. More in Setting up Cora Mobile.

Cora Max

Can one Cora Max show more than one tank?

Yes. One Cora Max can show every tank on your account, one at a time, and the Reef Room shows them all together.

What is "Primary Cora Max" and do I need to set it?

It decides which Cora Max talks to a tank's local equipment. Most people never touch it. With one Cora Max there's nothing to choose, and the default, Any active (automatic), lets every online Cora Max share the job. Pick a specific one only if you want a single device doing the polling. More in More than one Cora device.

Which device answers "Hey Cora" if I have more than one Cora Max?

Only one Cora device answers the wake phrase at a time. You choose it in Settings under Cora Assistant. Primary Cora Max is a separate setting for talking to your equipment. See Voice on Cora Max and More than one Cora device.

Does Cora Max need the internet to work, or just my home Wi-Fi?

Both. It needs your home Wi-Fi to reach your equipment, and an internet connection to reach Cora Cloud for sign-in, sync and the Assistant. The status tag in the top bar shows which one it has right now. More in The Cora Max home screen.

Does Cora Max keep working if Cora Cloud is unreachable?

Partly. It keeps showing the last data it has and keeps working with equipment on its own network. Sign-in, sync between devices and the Assistant wait until Cora Cloud is back. See The Cora Max home screen and Devices and device health.

Can I move my Cora Max to a different Wi-Fi network later?

Yes. On Cora Max, join the new network in its own network settings. Your tanks, devices and account stay the same. Only the Wi-Fi connection changes. More in Setting up Cora Max.

Phone app

Why does Cora Mobile ask for Local Network and Bluetooth access?

It needs Local Network access to find and pair a Cora Max or Wi-Fi equipment on your home network, and Bluetooth for equipment that pairs over Bluetooth. Without them, pairing can't find the device. See Settings and Troubleshooting.

Can two Cora Max screens show the same tank?

Yes. Add both to the same tank and they show the same live data. Primary Cora Max only decides which one talks to the local equipment. Both can still show the tank. More in More than one Cora device.

Can I check on my tank from my phone when I'm not home?

Yes. Your readings and history are always there through Cora Cloud, wherever you are. A few device settings only open while your phone is on the same network as the device. More in More than one Cora device.

Can I control equipment, like turning off a pump, when I'm away from home?

For most equipment, yes. Outlets, feed mode and similar controls go through Cora Cloud, so they work when you're away. A few of the device's own settings still need your phone on the tank's Wi-Fi. See More than one Cora device and Controlling your equipment.

Can two people use the same tank?

Right now Cora works with one account per tank. If someone else needs to see or help with a tank, share it with them. Don't sign in to the same account on two phones. More in Sharing.

Devices and integrations

What equipment does Cora work with?

A growing list of controllers and equipment, from Wi-Fi controllers to dosing pumps and gyres. For anything Cora doesn't connect to, you can log readings by hand. The current list is in Connections.

Is Cora affiliated with Neptune™, Red Sea™, Jebao™, or Maxspect™?

No. Cora isn't affiliated with, endorsed by, or partnered with any manufacturer it connects to. That includes Maxspect, whose integration is still in beta. Cora talks to their public accounts or local network protocols. A manufacturer's own app or firmware update can change or break that connection at any time, without notice. More in Connections.

Why can't Cora Mobile find my Cora Max when I try to pair it?

It's almost always Wi-Fi. Your phone and Cora Max need to be on the same network to pair, and on iPhone, Cora also needs Local Network access. Cora Mobile shows which pairing step failed and gives you a Retry button. More in Troubleshooting.

Does my phone need to be on the same Wi-Fi as my Cora Max?

To pair, yes. After that, everyday use works from anywhere through Cora Cloud. Only a few of the device's own settings need your phone back on that Wi-Fi. See More than one Cora device and Troubleshooting.

What happens if I change my Wi-Fi router or network name?

Any equipment or Cora Max on that network goes out of reach until it joins the new network or name. Reconnect each device the same way you first added it. More in Troubleshooting.

My device found nothing when I searched for equipment, what's wrong?

Check that the equipment is powered on and already set up in the manufacturer's app, if it needs one. Then check that your phone allows Local Network and Bluetooth access. Cora can't find equipment that has never joined your network. See Settings and Troubleshooting.

Why did my Red Sea device's readings stop updating?

When nothing on that tank's network is polling your Red Sea equipment, Cora shows a banner saying no device is reading it. Check Primary Cora Max in Settings, or open the tank on a device on the same Wi-Fi as the Red Sea gear. See Troubleshooting and More than one Cora device.

Why does it say "Could not reach the pump" when I try to control my Jecod™ pump?

The command didn't get to the pump. Usually it's off, off its network, or (for a Bluetooth-only pump) out of range. Check power and connection, move closer if it uses Bluetooth, and try again. More in Troubleshooting.

Why does the gyre program not apply?

Sending a schedule to a gyre can fail just like a command, because the gyre didn't respond. Check it's powered on and on its network, then try again from the schedule screen. See Scheduling equipment and Troubleshooting.

Is it safe to let Cora control my dosing pump automatically?

Cora only doses what you set up: a product, a strength and a schedule you define. If a dose stops partway, Cora raises an alert about it. It doesn't assume the dose finished, so nothing gets under- or overdosed without you knowing. See Dosing and Controlling your equipment.

What happens if a dose is interrupted halfway through?

Cora raises an alert saying the dose didn't finish and, when it can tell, how much went in. Read that alert before you assume the full dose was delivered, then resume or adjust. More in Controlling your equipment.

How does Cora know how strong my dosing product is?

It comes from the built-in product library, which lists salts and dosing products with their published figures. If you add your own product, you enter the strength yourself. More in Dosing.

Alerts and notifications

Why am I not getting notifications at all?

Check that the alert's category is allowed to send notifications under Settings → Notifications. Then check your phone's own notification permission for Cora. The daily briefing also stays quiet on days when nothing changed. That's normal. See Notifications and Troubleshooting.

Why is an alert not clearing even though the reading looks fine?

There are three usual causes. The reading is still out of range (check its history), the threshold doesn't suit your tank, or the source is reporting an out-of-range number (often a probe that needs calibrating). Usually you should fix the source and leave the threshold alone. See Alerts and thresholds and Troubleshooting.

How do I silence an alert temporarily without turning it off?

On Cora Max, tap Snooze. It mutes that alert on that screen for the cooldown set on the alert rule. The alert stays open and its threshold doesn't change. On your phone, set a longer Cooldown between alerts on the rule instead. More in Alerts and thresholds.

What's the difference between snoozing an alert and dismissing it?

Both are on Cora Max and only affect that screen. Snooze mutes the alert there for a while, and it comes back if the problem is still there when the snooze ends. Dismiss closes it there until the reading is back in range. If the problem comes back later, you'll get a new alert. More in Alerts and thresholds.

Can I set how long an alert stays snoozed, is a week the longest?

The snooze lasts as long as the alert rule's Cooldown between alerts, which you set in Cora Mobile. The longest is 1 week. More in Alerts and thresholds.

Why did I get an alert on my phone but not on Cora Max, or vice versa?

The switches in Cora Mobile's Settings → Notifications belong to your account, so they apply to every phone you're signed in on. Cora Max has no notification switches. It shows every alert at the wall, unless you've snoozed or dismissed it on that screen. If your phone stays silent, check that the category is switched on and that your phone allows notifications from Cora. See Notifications and Alerts on Cora Max.

Reef Buddy and Cora Assistant

What can I ask Cora, and what can't it do?

Cora Assistant answers questions about your tank's readings, history, dosing and journal. It can also carry out equipment actions you ask for by voice or text. It can't act on anything it has no data or connection for, and it tells you so instead of guessing. More in The Assistant.

Can Cora actually control my equipment, or just tell me things?

Both. Ask a question and it answers from your tank's data. Ask it to do something, like start feed mode, and it does it if the equipment supports it. See The Assistant and Voice on Cora Max.

Does Cora remember what I told it last time?

Yes, within the limits on the Assistant page. It can use earlier context about your tank, so you don't have to repeat yourself every time. More in The Assistant.

Why did Cora give me a wrong or strange answer?

Cora Assistant answers from the data it has for the tank you've selected. The usual causes are the wrong tank selected, missing readings, or a question that could mean two things. Check the tank picker or rephrase, and try again. More in The Assistant.

What is Reef Buddy and how is it different from the Assistant?

Reef Buddy is your daily briefing, written for you without you asking. It has a headline, two scores and the insights behind them. Cora Assistant is what you ask questions, whenever you like, by typing or talking. See Reef Buddy and the Glossary.

Languages

What language does Cora speak, and can family members use a different one?

Cora uses one language for the whole account. You can't set a different one per person or per device, so everyone signed in to that account sees the same language everywhere. See Settings and the Glossary.

I changed the language on my phone, why did my Cora Max change too?

Language is an account setting. Change it anywhere (your phone or any Cora Max) and it changes everywhere within moments. See Settings and the Glossary.

Will old reports and alerts be translated after I change languages?

No. Anything already written stays in its original language. New alerts, reports and Reef Buddy briefings use the new language from then on. See Settings and the Glossary.

Account, plans and privacy

What's free forever, and what needs a subscription?

Plans can change, so we don't list them here. The current plans, their limits and what each includes are on the Plans page in Cora Mobile and in Plans.

What happens to my data if my trial or subscription ends?

Your tank history isn't deleted. What changes is which features you can use. Plans shows exactly what each tier includes.

If I delete my Cora account, does that cancel my Apple or Google subscription?

No. Deleting your Cora account doesn't cancel a subscription you bought through the App Store or Google Play. Cancel it separately with Apple or Google. More in Settings.

Can I change or cancel my plan without losing my tank history?

Yes. Your tanks, devices and history stay with your account whatever plan you're on. Only the features you can use change. More in Plans.

What does Cora do with my tank data?

Cora uses it to show you your readings, run alerts and thresholds, and power Reef Buddy and Cora Assistant. What's stored and how it may be used is covered in Your data, Settings and the privacy policy.

Can I get a copy of everything Cora has stored about my tank?

Yes, you can export it from Cora Mobile. Your data explains what the export includes and how to ask for it.

If I delete my account, is everything really gone?

Deleting your account removes your data as described on the Settings page, including the choice about contributing anonymised data. If you want the exact detail, read Settings before you delete.

Troubleshooting pointers

Why does a widget show no value?

It's usually a connection problem. The parameter is still there. Check whether nearby widgets have the same problem, then look at the device's row under Devices. More in Troubleshooting.

Why does a reading say it's from an hour ago?

Because nothing newer has arrived. Some equipment only reports that often (an hourly titrator, for example). For anything else, check the device's row under Devices. More in Troubleshooting.

My device says "sign-in refused", what do I do?

The manufacturer's account rejected the saved sign-in. Almost always, the password was changed on their side. Open the device's row and sign in again. More in Troubleshooting.

Why does Cora Max show old data even though it says "Online"?

Online and Cloud both mean Cora Max itself is fine. If the tag shows either one and the data is still old, the problem is somewhere before Cora Max. Check the same tank on your phone. See Troubleshooting and The Cora Max home screen.

Why do my probe and my test kit disagree?

Cora is showing you a real disagreement. Nothing is broken. Calibrate the probe, retest with fresh reagent, and compare the two under the same conditions. An ICP result gives you a third number to compare. See Troubleshooting and ICP and health reports.

What happens if my internet goes down?

Cora Max and Cora Mobile keep showing the last data they received and keep working with equipment already on their own network. Sign-in, sync and the Assistant come back when the connection does. See Troubleshooting and The Cora Max home screen.

Does Cora work without internet?

Partly. Readings you already have, and control of equipment on the same local network, keep working. Sign-in, sync between devices, Cora Cloud storage and the Assistant need an internet connection. See The Cora Max home screen and Troubleshooting.

Still can't find your answer? Troubleshooting goes through fixes symptom by symptom, or you can email cora@coraiq.tech.

Written for Cora Max 0.28.79 and Cora Mobile 0.5.80. Last checked 2026-09-27.

Still stuck? Email cora@coraiq.tech and we'll help.