HiLo 4G Cellular Water Tank Monitor

Know how much water is in your tank, wherever you are

The HiLo 4G Cellular Water Tank Monitor sits on the roof of your water tank and uses radar to measure the water level. It sends the readings over the 4G mobile network to the free HiLo app on your phone, so you can check your tank from work, from town or from the other side of the world.

There is no Wi-Fi to set up, no cable to run back to the house and no display to mount on a wall. The monitor runs on its own replaceable battery and talks straight to the mobile network. That makes it a good fit for rural homes, farm and stock water tanks, baches, and lifestyle blocks where the tank is a long way from the house.

HiLo is developed in New Zealand by HiLo Level Monitoring (formerly Waterwatch). HiLo's level monitoring is used by homes, farms and councils across Australasia.

Radar level sensing: accurate, and nothing in the water

The HiLo uses industrial-grade radar to measure the distance from the top of the tank down to the water surface. HiLo quotes an accuracy of 0.2%. The sensor never touches the water, so there is no probe or float to rust, block, foul or wear out, and nothing extra inside a drinking water tank.

The HiLo app turns that reading into how full your tank is. Enter your tank's size or volume once during setup and the app shows the level for that tank.

4G cellular: made for tanks out of Wi-Fi range

Many tank gauges need Wi-Fi at the tank, or a receiver in the house. The HiLo connects to the 4G mobile network instead (LTE-M, also called Cat M1, a low-power network built for devices like this). It comes in two versions, one for the Spark network and one for One NZ. Choose the network with the best coverage at your tank. If you're not sure which that is, ask us when you book.

Because it uses the mobile network, a HiLo needs an annual subscription with HiLo. The subscription includes the network charges, and it's set up in the HiLo app when you activate the monitor.

Alerts that warn you before the tank runs dry

Running out of water is the problem you only find when the taps splutter. The HiLo watches the level for you and tells you when something changes:

• Low level alarm: time to cut back on water, order a water delivery, or check the roof and gutters.
• High level alarm: useful for overflow, transfer and top-up tanks.
• Rapid change alarm: a sudden drop can mean a leak, a burst pipe, a broken trough or a tap left running.
• Sensor offline alert: if the monitor stops reporting.
• Low battery alert: when the battery drops below 10%, so you can replace it in good time.

Alerts come through the app, and email and text (SMS) alerts can be turned on for each person. Alarm levels are set in the app, remotely or on site over Bluetooth.

Share your tank with the whole household or farm team

Invite family members, farm staff or a property manager to your HiLo account so they can see the tank level and get the alerts too. Readings can be exported to a spreadsheet (CSV), and HiLo has a REST API for anyone who wants to connect the data to their own farm or building systems.

How often does it report?

By default the HiLo measures the water level every 15 minutes and sends the readings to the app every 6 hours. Both can be changed: measurements from every 5 minutes to every 24 hours, and transmissions from every hour to every 24 hours.

HiLo 4G tank monitor specifications

Model	HiLo 4G Cellular Water Tank Monitor (T35)
Sensor	Radar, non-contact
Accuracy	0.2%
Measuring range	0.2 m to 3.5 m from the sensor to the water surface
Network	4G (LTE-M / Cat M1), Spark or One NZ version
Power	Replaceable battery, life expectancy 5+ years
Weather rating	IP68 waterproof, UV resistant
Tanks	Plastic and concrete, one monitor per tank
Reporting	Measures every 15 minutes, sends every 6 hours (adjustable)
Alerts	App, email and text (SMS)
App	Free HiLo app for iPhone (App Store) and Android (Google Play)
Subscription	Annual HiLo subscription, includes network charges

Installing a HiLo water tank monitor

HiLo designed the monitor so a handy owner can fit it. The app's setup wizard connects to the monitor over Bluetooth and walks you through drilling, measuring, mounting and checking the first readings. HiLo's installation guide covers the details that make the difference between good readings and poor ones:

• Hole: a 50 to 60 mm hole in the tank roof for the radar to see through. A standard hole saw works on plastic tanks. Concrete tanks need a diamond core drill.
• Height: mount the monitor at least 300 mm above the highest water level the tank can reach.
• Level: the sensor needs to sit within 3 degrees of level. On sloping or domed roofs, angled shims are used to level it.
• Position: the centre of the roof is usually best on plastic tanks. Devan tanks need the monitor off-centre, because metal in the centre interferes with the radar. On concrete tanks it goes high and off-centre, levelled with shims.
• Clear view: keep the area under the sensor clear of ball cocks and inlet and outlet pipes.

Want us to install it? Aqua Works fits HiLo tank monitors

If you'd rather not climb on the tank with a drill, we'll do it for you. Our team installs tank gauges across Rodney and North Auckland, from Mangawhai to Albany. We'll:

• pick the right spot on the tank roof, clear of pipes, ball cocks and anything metal
• drill the hole with the right tool (diamond core drilling for concrete tanks)
• mount and level the monitor so it reads accurately
• set up the HiLo app on your phone, enter your tank size and set your alarm levels
• add anyone else who needs the alerts, and check the first readings before we leave

Got two tanks? Each tank needs its own monitor, and we can fit them all in one visit. We can also add a HiLo when we install a new water tank, or while we're on site servicing your UV system or water pump. Planning a full rainwater harvesting system? A tank monitor is one of the most useful parts of it.

Want your HiLo fitted by a local plumber?
Call us on 0800 278 296.

HiLo 4G tank monitor: frequently asked questions

Do I need Wi-Fi at my tank?

No. The HiLo 4G connects to the Spark or One NZ mobile network, so it only needs 4G coverage at the tank. If you have good Wi-Fi at the tank, HiLo also makes a Wi-Fi model. Ask us which suits your property.

Is there an ongoing cost?

Yes. The 4G monitor needs an annual subscription with HiLo, which covers the mobile network charges. You set it up in the HiLo app when you activate the monitor.

Will it work on my tank?

It works on plastic and concrete tanks. The radar reads from 0.2 m to 3.5 m below the sensor, and the sensor sits at least 300 mm above the top water level, which suits most home and farm water tanks. Send us a photo of your tank if you're unsure.

How long does the battery last?

HiLo gives the battery a life expectancy of more than 5 years. It's replaceable, and the app warns you when it drops below 10%. Replacement HiLo batteries are in our shop.

Spark or One NZ: which should I choose?

Choose the network with the strongest 4G signal at your tank, not at the house. If your phone is on Spark or One NZ, its signal at the tank is a good guide to that network.

Can more than one person get the alerts?

Yes. Invite other people to your HiLo account and they can see the tank level and choose how they get alerts: app, email or text.

Can I install it myself?

Yes, HiLo designed it for DIY installation, and the app's setup wizard guides you through it. On a concrete tank you'll need a diamond core drill. If you'd like it done for you, call us on 0800 278 296.