Pool water monitor comparison

ICO vs Sutro

Sutro shut down in 2025. Here is the straightforward replacement decision.

By Brian Williamson, Pool Express product specialist Published November 4, 2026

Winner: ICO Pool

This one is not close: do not buy Sutro old stock. Its service is off and its cartridges and parts are no longer supported. ICO is a current, cartridge-free replacement with hourly readings and owner-replaceable probes.

Why I'd choose ICO

Active app, product stock, and U.S. support
Hourly pH, ORP, and temperature readings
No reagent cartridges or required subscription
Replacement probes with public prices

See ICO Pool View every comparison

My pick

ICO Pool

Current product · hourly readings · no cartridges or subscription

Discontinued Sutro smart pool monitor, discontinued

Sutro Smart Monitor

Discontinued · app and cloud service ended October 31, 2025

Important: Sutro's official notice says its app and monitor stopped functioning after October 31, 2025. Old stock cannot provide water readings.

The simple comparison

What matters	ICO Pool	Sutro
Current status	Available and supportedEdge	Discontinued October 31, 2025
Water readings	Every hourEdge	None · cloud service is offline
Consumables	No test cassettes or reagentsEdge	Used reagent cartridges · no longer available
Connection	Direct 2.4 GHz Wi-Fi + BluetoothEdge	Cloud-dependent service shut down
Replacement parts	Separate pH, ORP, and TDS probesEdge	None available
Should you buy it?	Yes, if its measurements fit your poolEdge	No · even unopened old stock cannot report chemistry

This is less of a comparison and more of a warning. Sutro was a cartridge-based smart monitor, but its readings depended on the company's app and cloud service. That service ended on October 31, 2025.

What happened to Sutro

Sutro's official shutdown notice says the monitor and app no longer function after the service date. The store also closed, which ended the normal supply of reagent cartridges and parts. The hardware may still float, but it cannot do the job it was built to do.

This is the risk with a connected product that needs both a cloud account and proprietary consumables. Once either disappears, perfectly clean hardware can become useless.

Why old stock is a dead end

An unopened Sutro is not a bargain. There is no active service to turn on, no working app path for chemistry readings, and no supported cartridge supply. I would not pay any amount for one as a pool monitor.

If a marketplace listing still describes Sutro as active, the listing is out of date. The shutdown date—not the condition of the box—is what matters.

What I want in a replacement

ICO measures pH, ORP, and temperature each hour; ICO Salt also measures salt and TDS. It does not need reagent cartridges, and its app has no required subscription. Its pH, ORP, and TDS probes are separate $149 parts.

That does not make any connected product immortal. Apps and online services can always change. What I like about ICO is that the routine wear items are standard replaceable probes, the prices are public, and the monitor does not depend on a stream of proprietary test cartridges.

Final call

ICO wins by default because Sutro no longer works. For a former Sutro owner, ICO is a practical current replacement if hourly pH and ORP trends fit the way you manage your pool. Keep a manual test kit for full chemistry checks, and do not buy leftover Sutro inventory.

See ICO Pool and choose your water type →

Common questions

Does Sutro still work?

No. Sutro's official notice says the app and monitor stopped functioning after October 31, 2025.

Can I activate an unopened Sutro?

No. The cloud service and app are no longer active, so new-old stock cannot provide chemistry readings.

Is ICO completely independent of online services?

No connected monitor should be described that way. ICO uses an app and online features. Its practical advantages are no paid plan, no test cartridges, direct Wi-Fi/Bluetooth connectivity, and owner-replaceable probes.