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

I had the V1 of this and then later bought the V2 — and I love both. The updates are noticeable and it works even better this time around. Makes pool maintenance so much easier and less of a chore. Sturdy, reliable, and genuinely helpful to have around. Highly recommend if you want something that actually simplifies the job!

Terrible product. My first cassette only lasted a week and 3 cassette cost 70$ It only tests chlorine and ph, does not test anything else. Total waste of money.

Purchased my WaterGuru in 2024, and in December of 2025, it kept failing to measure. I contacted customer support and it turns out I had a bad motor on my unit. Joan was awesome and ended up sending me a new unit for no charge. I will admit, before the unit crapped out on me, WaterGuru has made it super easy to help maintain the proper chemicals in my pool year-round.

This is a great product, would give 5 stars but you need to understand the measurement you get on a daily basis. Once you look for a trend going on a direction then you make an adjustment. As an example chlorine will be high one day low the next. But over a few days you get the feel of what is really going on. If you don’t like testing with the kits this is worth the cost. But be warned the re-lacement test cartridge are pricey

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.

Worked for about 4 months. Then stopped with daily measurements. Gave manual readings for about a month and now won’t give readings at all. The cassette is supposed to last 30 days but it does not. I have them on automatic shipment and have a bunch of useless cassettes. I consulted the help section and done everything suggested to resolve the issues. For a $400 device it’s absolutely ridiculous. I have contacted customer service, will update review.

This looked like an easy, automatic way to track my pool chemistry. In reality, not so much. My CYA only went up 3 ppm according to this unit after adding 1.67 gallons of liquid stabilizer, but my drop kit showed the correct jump. Alkalinity has been off by nearly 30 points compared to manual testing. Free chlorine and PH are sometimes close, but often not. And calcium readings swing even with no chemical changes. The device looks cool and it’s fine if you just want to see whether things are generally going up or down, but you’ll still need a manual drop kit for actual dosing decisions, soooo… there’s that. Was hoping this would really work, but moving back to drop testing to stay accurate

There's really a lot to like about Waterguru, but it does have a significant weakness. First of all, the good news. Installation is a breeze compared to some of its competitors. It's easy to unpack and drop into the skimmer (though the instructions for how to get into the battery compartment could do with some work!). I especially liked the way the device connects directly to your home wifi from the skimmer. This means you don't need to install a separate communication hub near to the pool or in the poolhouse. In addition, a skimmer-based installation means there's nothing floating around in the pool for swimmers to bump into (or to tie up somewhere). It also means the Waterguru monitors and reports the water flow rate to your pump which I've not seen with any other device. I especially liked the way it also reports the level of cyanuric acid ("stabilizer"). I like to keep stabilizer levels low in my pool so that the added chlorine has maximum effectiveness. This means monitoring the stabilizer level so it doesn't get too high is important to me. Three other positive points: (a) It uses regular batteries, so you can use standard and inexpensive rechargeable NiMH or Lithium cells (b) there's no subscription plan so you buy new test cartridges whenever you want to and use them at whatever rate is convenient for you, and finally (c) the free chlorine meter goes all the way up to 10ppm which is great for monitoring the effectiveness of your weekly or bi-weekly pool shocks. Unfortunately, what really let Waterguru down for me was the inaccuracy of its measurements. Even the simplest of tests (pH) was out by quite a large margin (down by 0.4) against pool shop water testing and my electronic meter. Alkalinity bounced around all over the place but was generally 30% too high. The worst inaccuracy, however, was Free Chlorine. Even in a well-managed pool in which Free Chlorine and Total Chlorine were kept within 0.1 ppm of each other, the Waterguru reported Free Chlorine levels that were high by 2ppm or more (e.g. 2.8 ppm was reported as 5.2 ppm, 4.8 ppm was reported as 6.9 ppm etc. This is bad news because if you take the Waterguru measurements at face value you'd hold off adding more chlorine, when in reality you need to continue with the regular dosing regimen to maintain adequate sanitation. In summary, it's a good design, it's easy to install, it offers pool flow and cyanuric acid measurements as well as the usual tests, but ultimately, I sent mine back after 14 days due to the inaccurate numbers. I'm hoping the second generation of product will be more accurate in which case I'll look forward to trying it again.