Old phone as an aquarium camera: placement, power, heat

Most of us have an old phone or two sitting in a drawer. They come with a camera, a microphone, Wi-Fi and a battery that keeps them running for a while during a power cut, which makes them a great fit for watching an aquarium. But a phone that lives next to water and stays plugged in all the time needs a little thought about placement and safety. The tips below apply whichever app you use.

Check the phone first

• OS version: most monitoring apps have a minimum OS version, so check before you install.
• Camera and microphone: no cracks in the lens, focus works, and the microphone records normally.
• Battery health: if the screen is lifting or the back is bulging, the battery may be swollen. Don’t use that phone plugged in long term. If the battery is badly worn and drains very fast, consider replacing it first.
• Tidy up the phone: uninstall apps you don’t need and turn off other apps’ notifications to reduce background activity and heat.

Placement: a clear view, and a safe spot

Distance and angle

• Frame the whole tank with a little margin around it. Too close and you can’t see everything; too far and you lose detail.
• Don’t shoot straight at the glass. Angle the phone about 15° to the front panel: this cuts glare from the glass noticeably and keeps the flashlight from reflecting straight back.
• Aim the lens at roughly the middle of the tank so you can see both the surface and the area near the substrate.

Avoid glare and backlight

• Windows, room lights and the tank light all create reflections on the glass. Open the camera preview and move the phone to the spot with the least glare.
• With a bright window behind the tank, the picture tends to go dark. Avoid backlighting where you can.
• Wipe the lens and any water marks on the outside of the glass regularly; the picture will be much clearer.

Stable and dry

• Hold the phone in a sturdy stand rather than propping it against the tank. If the phone gets knocked, it won’t see the tank any more.
• Don’t put the phone on the tank lid or above the water: condensation fogs the lens, and a phone sliding into the tank is dangerous for your fish and for electrical safety.
• Put the stand where pets and small children can’t easily knock it.

Power: if it’s always plugged in, plug it in safely

• Use the original charger and cable, or good-quality replacements, and replace any damaged cable.
• Leave a drip loop in the power cable: let the cable dip below the outlet before rising up to it, so any water running along the cable drips off at the lowest point instead of running into the outlet.
• Mount the power strip up high, away from water, ideally one with GFCI (RCD) protection.
• If you want the phone to detect power cuts, plug its charger into the same power strip as the filter. That way the phone notices when the breaker trips or the strip is switched off.

Heat and battery care

Staying at 100% charge while running warm is the main cause of battery aging and swelling. Here’s what helps:

• Turn on the system’s built-in charging protection: on iPhone, turn on Optimized Battery Charging, and newer models can also cap charging at 80%. Many Android phones have options such as “Adaptive charging” or “Battery protection”; where they live varies by brand, so look in the battery settings.
• Take off thick cases so the phone can shed heat more easily.
• Keep it out of direct sunlight and away from the tank light, heater and other warm equipment.
• Turn screen brightness all the way down, or use an app that dims the screen automatically. It saves power and reduces heat.
• Check once a month whether the phone is getting hot or swelling. If something seems wrong, unplug it right away and stop using it.

Network and system settings

• Put the phone where the Wi-Fi signal is steady; a weak signal makes the live view stutter.
• If the phone has a SIM slot, a data SIM lets it send alerts over mobile data when the router loses power.
• Turn off auto-lock, or follow the app’s instructions to keep it running in the foreground. On Android, also exempt the app from battery optimization and allow it to run in the background, or the system may close it.

Keepova makes it easier

Keepova walks you through all of this during first-time setup: a live preview helps you find the angle with the least glare, you outline the tank, and everything outside it is masked before any image is uploaded; you get brand-specific instructions for keeping the app alive and for battery settings; and at the end you’re asked to unplug the charger once to test that alerts get through. While running, it keeps monitoring the battery temperature, scales back and alerts you if the phone gets too hot, and reminds you once a month to check the battery for swelling.

An old phone can keep an eye on your aquarium, but it’s still an electronic device that stays plugged in for months. Get the placement and electrical safety right, and it can look after your tank safely for a long time.