WaterGuru Sense S2 Smart Pool Monitor – Digital Pool & Spa Water Tester for Chlorine, pH, CYA & Alkalinity – Wi-Fi Enabled – Includes C5 Cassette, Float Ring & Batteries

works as advertised. I got this to replace my Surtro when they went out of business in 2025. I would buy it again, makes owning a pool a lot less work!

DO NOT purchase!!!! First which really isn’t advertised, you spend $350 for basically a drain cover and holder for the testing/sending cartridges which must be replaced every 30 days. When the cartridge reaches 30 days it stops testing the water and updating the app. Here is the kicker you can only buy the cartridges directly from Waterguru for around $80, but they are supposedly having supplier issues getting the replacement cartridges and you cannot get them. So after 30 days and spending $350 the Smart Pool Monitor is useless and dead in the water…. This company is scamming people selling products that will stop working in 30 days.

Easy setup, use it for hot tub water quality monitoring. It is simply awesome, and very accurate as compared to traditional methods of water analysis (i got a classic Taylor kit as well, measurements are essentially identical, made me use the Taylor much less often, about once a month). Setup instructions were clear and once you have the app everything is super simple. Connectivity (mentioned by many) is not an issue at all, it’s just slow to connect that’s all, but this is not a medical emergency :) and does end uo always connecting either through bluetooth if you are close by or WiFi if you are not home. I was a bit skeptical reading some of the reviews, but really glad i gave it a go. 5 stars easily and thumbs up.

I had been one of the earliest pHin users, until Hayward acquired it and then eventually shut it down. I can understand why, since I had received in total 5 warranty replacement units. Then, I decided to go without a monitoring device for one season, which worked fine, until it didn't this year, when I went on a two week international trip and then I returned to a full algae bloom. My gamble that I would be back in time did not pay off, so I got the WaterGuru2 to stop flying blind and Wow! it's so great to have this level of fine grained data. I had been toying with Pentair pH & CL test kits and then the Taylor test kit too, but now I always exactly where my measurements are at. Now I've got a much better handle on all the major variables in my pool, which actually took a while to fully understand since I didn't know any of this before. As you can see from my screen shots, my pH is currently a bit low, but I'm told that's reasonable since I use the Tri-Chlor slow dissolving tablets, but my CYA (CYanuric Acid) is through the roof too high. We figured out today that this is because I had been using 99% DiChlor to shock my pool, which spas like to use, but it's not appropriate for my pool, so I need to switch to 68% Calcium Hypo. I'm also going to see if a new CYA remover does what it says it can do, to get my CYA down to normal levels. I'm also going to add in Green to Clean since my high CYA is preventing the full killing of some nagging algae that still remains and likes to come back. The WaterGuru support team, both Tier 1 and Tier 2 have been a true pleasure to work with. With your purchase of the WaterGuru2, you get two types of Sense2 cartridges, 1 C5, which monitors pH, FC plus CYA, Hardness and total Alkalinity and lasts 30 days, and 2 C2's, which measures just pH and FC daily and these each last for 60 days. Once you get into a steady state C2's are enough. By the way, if you're recovering from something as bad as an algae bloom, please refrain from excessively invoking "Measure" on the WaterGuru2 app, since this will shorten the life of the cassette dramatically, since the measuring film scrolls through the cartridge and it will run out faster. By default the WaterGuru2 measures the water once a day and that's actually good enough for residential owners. Anyone who loves data and is tired of "winging it", or "excessively shocking your pool", or "just paying too much monthly to your pool person" should get a WaterGuru 2.

Pros: Testing seems to be pretty accurate. App is free and makes it convenient to monitor the pool conditions. The app gives suggestions and tips on improving various levels. Cons: Testing is done through cartridges. If you only test the water once per day, each cartridge will last about a month. A 5-pack of cartridges is $150... which is a little spendy. My biggest complaint is the battery life. The unit takes 4 C-cell batteries that only last about 2 weeks (based on Arizona heat in July-Aug). I would think a solar powered unit would be a better eco-friendly option.