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This svelte, floating device offers 3 years’ worth of pool measurements. But understanding its measurements might require some effort on your part. Flowmeter
$329.00 (full kit with Wi-Fi bridge); $279.00 (replacement monitor and chemicals only)
Keeping tabs on pool chemistry is a constant hassle, but serious consequences await those who fail to do so. Should your pool chemicals get out of balance, you can quickly end up with a massive algae problem and/or permanent damage to the pool plaster—not to mention an unusable eyesore. And it can be a major, expensive slog to get things back to normal.
Weekly testing is mandatory, and devices like the WaterGuru Sense have made it easy to check your pool chemistry on a daily basis without having to break out sample kits and testing strips. And while WaterGuru works pretty well, it’s expensive, requiring costly replacement cartridges that carry the chemical reagents needed for its daily analysis.
Upstart ioPool offers another solution. The Eco (styled EcO) Start is a (largely) self-contained device that bobs in your pool like a floating thermometer. The device measures 9 inches high and weighs just 5 ounces, and it works with no replaceable components—not even batteries; all of its chemical testing reagents are sealed inside. The Eco Start has an estimated lifespan of three seasons, though the company says a 2024 update will extend that to four. (In ioPool’s parlance, a season is one swimming season, i.e., a summer. The unit doesn’t work when the water is too cold, and users are directed to remove it from the pool and store it in a specific manner during winter months.) A separate version of this product, the ioPool Eco Start Salt, is designed for use with saltwater pools and is not reviewed here.
The ioPool Eco Start’s best feature is how frequently it measures your pool’s conditions: every 15 minutes.
I’ve been using the product for much longer than the typical review period would entail. I received the ioPool Eco Start Pool Monitor in August 2023 and started testing in the later summer months of 2023, stored it for the winter, and started up again at the beginning of warmer months of 2024.
The ioPool Eco Start Water Monitor last four years, but you should need to buy the ioConnect Bluetooth-to-Wi-Fi bridge just once.
The ioPool Eco Start Water Monitor last four years, but you should need to buy the ioConnect Bluetooth-to-Wi-Fi bridge just once.
The ioPool Eco Start Water Monitor last four years, but you should need to buy the ioConnect Bluetooth-to-Wi-Fi bridge just once.
The device is unique in its setup, requiring that one end be physically disassembled and put back together in a certain way, so as to expose its sensors to the water when it’s submerged. It’s a simple process, but one that requires careful attention to detail (and following the instructions in the app). A separate Wi-Fi gateway (included) connects the ioPool’s Bluetooth radio to your home’s 2.4GHz Wi-Fi network. The gateway must be connected as close as possible to the pool, but it isn’t weatherproof, so you’ll need to plan accordingly. I encountered some hiccups during the wireless setup, likely related to signal strength, but this eventually resolved with a little trial and error around device placement.
Once connected, your first step is to calibrate the unit. Classic-style color-changing test strips are included that allow you to make a manual analysis of your pool’s chemistry. Dip one in the water and compare it to the included chart (on printed cardstock), then feed the values to the ioPool app. This calibration needs to be performed at the beginning of each season, so make sure you keep tabs on the box of supplies over the long run.
After that, you just toss the ioPool into the water and you’re on your way. (Note that you must leave it in the pool for the season; the sensors will fail if they dry out.)
The ioPool app is straightforward, with three primary measurements about your pool presented front and center: disinfection potential, pH, and water temperature. The last two are straightforward; it’s the first one that’s unique to ioPool. ioPool doesn’t report free chlorine—the standard of pool disinfection standards—but rather reports ORP, or oxidation-reduction potential. ORP doesn’t just measure free chlorine (FC) but rather “active chlorine,” which is measured electrically, not chemically. Pool water is generally thought to be safe between 700 and 750 millivolts, though converting that measurement to FC isn’t straightforward.
Pool-water conditions are color-coded in ioPool’s app, to provide an at-a-glance understanding of any problems brewing. Long-term trends are tracked for up to 3 months at a time, but only daily averages are reported.
Pool-water conditions are color-coded in ioPool’s app, to provide an at-a-glance understanding of any problems brewing. Long-term trends are tracked for up to 3 months at a time, but only daily averages are reported.
Pool-water conditions are color-coded in ioPool’s app, to provide an at-a-glance understanding of any problems brewing. Long-term trends are tracked for up to 3 months at a time, but only daily averages are reported.
ioPool says that ORP is much more accurate, but the catch is that by and large, the industry uses free chlorine, and most pool owners have a clear understanding of how FC works. (Get below 2ppm FC for long and you will soon have a green pool.) This is probably because it’s harder and costlier to measure ORP, requiring an electronic device instead of chemical strips or vials of reagents. So, the big question with ioPool is whether you’re willing to recalibrate yourself to understand ORP readings instead of FC. That said, it’s possible that ioPool will someday relent and add a measure (or estimate) of FC to its app. So far, it’s holding out.
I’ve been running ioPool side by side with a WaterGuru Sense for the duration of my testing and they generally compare fairly closely. ioPool’s pH readings have been more accurate than WaterGuru’s when compared to standard analog tests, regularly varying from WaterGuru’s numbers by up to 0.3—sometimes higher, sometimes lower. ioPool’s disinfection potential number (which is more important), on the other hand, is often well-correlated with the FC rating in the WaterGuru app. If I’m in the green on one app, I can usually be sure I’ll have a green reading on the other. Finally, when it comes to temperature, ioPool’s number is invariably 3 degrees higher than WaterGuru’s. That’s likely because ioPool’s device bobs in open water while the WaterGuru is in shadow in the skimmer.
Perhaps the best feature of the ioPool system is how frequently it measures conditions. Unlike the once-a-day WaterGuru, ioPool measures conditions every 15 minutes and logs them all in the app. Unfortunately, ioPool’s logs aren’t as helpful as WaterGuru’s, only logging a daily average of conditions instead of all of them, and only going back three months. This isn’t me being pedantic: It can be very instructive to see conditions immediately before and after a chemical addition. Naturally, ioPool also offers suggestions on how to correct any conditions in your pool that might not be in the green zone, and it sells a wide range of chemicals via its in-app retail store to help you out on that front. I haven’t used any of ioPool’s chemicals.
The ioPool EcO Start isn’t cheap—nothing involving your pool ever is: the starter kit of monitor and Wi-Fi gateway runs $329. (The Salt version is $349.) That’s comparable to the price of the WaterGuru Sense S2, although the former will only last for 3 years and the latter requires up to $120 of extra consumables each year. Ultimately, I think it’s a wash.
The ioPool’s simplicity—and its testing frequency—is a big improvement over the clunky (yet largely invisible) WaterGuru. If I can get my own mind recalibrated around ORP, it might become my go-to. For now, I’ll continue to use both.
Ec Controller Christopher Null is an award-winning technology journalist with more than 25 years of experience writing about and reviewing consumer and business tech products. Previously, he served as Executive Editor for PC Computing magazine and was the founder and Editor in Chief of Mobile magazine, the first print publication focused exclusively on mobile tech. In addition to covering a wide range of smart home gear for TechHive, he is a frequent contributor to Wired, This Old House, and AAA’s Via Magazine.