Why is Sutro Better?

Why is Sutro Better?

We get this question all the time and it’s time we answered it!

Fives Years And Two Continents Development

Ravi (Center) with his Sister and Pool Tech Martin at the Family Pool Store

Sutro started 5 years ago. Ravi Kurani, our founder and CEO, had an idea — how to “fix” water.

Ravi worked at his dad Harry’s pool store when he was a kid. He was also a pool boy who has probably done way over 10,000 manual tests in his lifetime. Ravi knew that the majority of problems that he had to fix were due to inconsistent pool testing. Roughly his Dad’s shop would get panicked, customers would call that their pool was green, or foaming, or smelled funny and that they needed to get their water fixed pronto.

Ravi went to college in Riverside and got a degree in Mechanical Engineering. He was, albeit briefly, a rocket scientist with NASA (JPL to be exact), working on a more effective way to burn rocket fuel. Sounds fun huh :-).

Ravi’s curiosity and entrepreneurial spirit led him to India where he worked on solving the problems with contaminated water. It turns out that the majority of the world’s problems revolve around having access to clean water.

Insight #1: Be an Expert in What You’re Trying to Solve 

It’s All About What’s in the Water

Ravi’s adventures in India gave him the idea that before you can treat water, you have to test it to see what’s wrong with it. Sounds simple enough but you’d be surprised that no one was doing that. The problem, as Ravi will tell you, is trying to sell a new technology to a government is like climbing a pole slick with grease — you never seem to get anywhere.

Once Ravi came back home, he realized that his ambitions to make water safe had to start small — like the size of your backyard pool; small.

A Backyard Chemistry Experiment

No PhD Required

If you have a pool (or spa for that matter), you know that it’s really a large backyard chemistry experiment that will test your mental and physical patience and prowess. Water is complicated. Even though it’s a simple bonding of Two Hydrogens and One Oxygen and it makes life on earth possible. In fact, it’s essential for every single living thing on planet earth including green, mustard, and black algae that live in an untreated pool.

Your backyard chemistry experiment is complex and needs a lot of TLC in order to make it safe for you to swim. Ravi’s experience taking care of over a 1,000 pools taught him that consistent testing, that’s accurate, will keep your pool (or spa) water safe. That led him to develop the first Sutro prototype.

Insight #2: Take a manual process and automate it to make it repeatable and more accurate.

The Problem with ORP

Our Friend (and Inspiration), the Roomba

The first Sutro Smart Monitor used a technology called ORP (you can see our demo at TechCrunch back in 2015 at CES’s Hardware Battlefield). The two wires sticking out of the chlorine floater are nothing but a pH and ORP sensor. ORP stands for Oxidation-Reduction Potential. It measures the oxidizing properties of any sanitizer present in the water. When chlorine is free to oxidize, sensors generate a millivolt reading, expressed as ORP. If the chlorine isn’t free and available, a millivolt reading will not be generated. At the time, ORP was the go-to method to measure this because it was electronic meaning you did not have to do the manual process of dropping chemicals into a flask of water.

The problem with ORP (which Ravi figured out 3 years ago) is that it drifts all over the place and the sensor needs to be calibrated with a known standard. This is cumbersome and leads to all sorts of inconsistencies in measurements.

As an example, ORP measurements vary by time of day since sunlight (actually the UV part of sunlight) will cause cyanuric acid (CYA) and chlorine to combine, which makes the chlorine less free to do its job. It still can mind you, but any ORP reading will “show” that it can’t. Or that the pump running can send signals through the water which will affect ORP and cause it to go wacky. Kind of like passing through a metal detector if you have a pacemaker or a titanium hip.

The first ORP Smart Monitor had lots of problems that nearly bankrupted Sutro. It was only through Ravi’s hard work, pool boy experience, and mechanical engineering background that he realized the best way to test water would be to create a “mini pool boy” robot (like the Roomba vacuum). He thought why not take the dropping chemicals in a tube of water and create a robot that would do it.

Insight #3: The “easy” way did not cut it and was wildly inaccurate.

A Roomba For Testing Water

Our Friend (and Inspiration), the Roomba

You have probably seen a Roomba or know someone that has one. For those of you who don’t know what a Roomba is, it’s a robotic vacuum cleaner that learns your rooms and vacuums them automatically. It’s probably the best comparison we can draw for the Smart Monitor. Just imagine a Roomba in your pool sans the vacuuming.

The Roomba was first introduced in 2002 by a company called iRobot. iRobot was founded in 1990 by Massachusetts Institute of Technology roboticists with the vision of making practical robots a reality, iRobot has sold more than 30 million robots worldwide. Currently a Roomba sells for ~$299, depending on the model.

Robots Do a Lot of Work

Robots perform functions that humans can do as opposed to passive electronics or just a sensor. All this work, especially the moving of things in physical space, takes a lot more effort and smarts to make it work. If you compare the process of taking a Smart Monitor Measurement vs an ORP Measurement, you’ll see what I mean:

The first part of our process relates to taking in an actual sample of the water and adding drops of reagents — just like you would do with your home kit. That’s the robot part and while it’s more complicated (and costly), it’s the most accurate way to do it.

The pumps, flow cell, titration and precision syphoning is where the majority of the cost adder comes from (about 35-50% of the total cost). That’s why we have to charge more. It’s worth it (to us anyway) because if we get accurate measurements of pH, Chlorine, and Alkalinity, we can give you the best treatment recommendations. 

Insight #4: The mechanicals add an additional 35-50% to the cost of the device.

The Gold Standard for Over 100 Years

Reagent based testing or dropping chemicals into a tube of water is the gold standard for water testing. Every single time you pull out your pool test kit, stick your hand up to your arm to get a sample and put five drops of phenol into it, you’re performing the most accurate way to measure the chemicals in water. It’s been done that way for over 100 years.

Reagent based testing is how every single water company, the FDA, the EPA, and anyone who wants an accurate and reliable measurement does it. Honestly, it’s how our drinking water is measured. It’s time-consuming and usually takes a human to perform (even if put into a machine like a Spin Touch) but it’s the best way to do it, hands down.

The Sutro Smart Monitor


It Measures What Matters

The most important four measurements you can take for your pool are temperature, pH, Free Chlorine, and Alkalinity. Those four form the basis of determining the health of your water. Sure, there are a bunch of others (you’ll get 7-9 when you go to the pool store, except temperature of course) but for daily measurements to see how your water is doing, those four will give you all you need.

It Weighs Like 10 pounds!

The first thing you will notice when you hold a Smart Monitor in your hand is that it weighs a lot. Actually, it’s 4.85 pounds to be exact. The weight is to keep it upright in your pool but it’s also all those pumps to make sure we get a good sample of your water.

It’s as Big As Your Arm!

The smart monitor is big for a reason — we need to get an accurate sample of your water. It’s the same type of sample you’d get if you use a strip or reagent drop test. Recall that the instructions tell you to “take a measurement almost up to your shoulder below the surface of the water.” The reason for that is that anything shallower (between the surface and your arm depth, like 18 inches) will not be representative of your actual water chemistry.

Water near the surface has very different chemistry than below the surface. I’m sure you have seen that when you look at the surface of your water and sometimes see a sheen. That sheen can go deeper than the surface and can throw off your measurements. That’s why you have to take a sample deeper under the surface.

Insight #5: It’s built to last and that’s why we guarantee it!

It Takes 3 Measurements A Day

The smart monitor measures the temperature, pH, Chlorine, and Alkalinity of your pool three times a day. To date, we have taken those four measurements over 94,377 times in the pools we are monitoring.

If you realize that each measurement would take you 3 minutes (on average), that’s a total of 

283,131 minutes or 4,718 hours, or 196 days of measurements. 

All those measurements are fed into our recommendations engine to make it better everyday. Sure, we’re not perfect yet but every day we (and our recommendations engine) learns how to treat your water better.

All that knowledge and data will save you not only money but a lot time. That’s the time you can spend enjoying your pool.

Insight #6: More data that accurate = Better Recommendations

It Allows You to Use Your OWN Chemicals

Pick Your Favorite. Sutro works with them ALL

We want to be the best pool (or spa) water testing company on the planet. That means we’re going to focus on the technology to accurately test water and not the chemicals to treat water.

Ravi actually went down that path and it turns out it was a bad path to go down. You see, making, shipping, and selling chemicals is a complex business. There are also over 5,000 different brands to choose from and everyone has their favorite. We decided to focus on what we do best, technology, and leave the chemicals to all the great pool and spa retailers.

Did I Keep my Promise? 

Ravi (Left) and Me (Right) at the Atlantic City Pool & Spa Show 2020

So there you have it. The reason why Sutro costs $699 is that we are a robot that pulls an actual sample of your water to measure it using the gold standard of regent testing that the FDA, EPA, and others use. That’s why we are double our competitors (at least for now).

Insight #7: The Robotics are why we are double in price

I hope you might consider investing in a Smart Monitor to keep your pool (or spa) crystal clear.

Here’s what you get!

We know that it’s important to test your pool (or spa) water regularly to ensure that it’s crystal clear and ready for a swim. An investment in a Sutro Smart Monitor will ensure that you’ll always be ready for a swim. Here is what you get when you invest in the best pool (and spa) water testing robot:

  • Monitor + Hub + 2 rechargeable Monitor batteries.
  • Automatically measure pH, Chlorine, and Alkalinity 3 times a day
  • One Year of cartridges (shipped monthly) + monitoring
  • iOS + Android App
  • Expert treatment recommendations based on Your Chemicals.
  • 60-day no-hassle money-back guarantee
  • Phone + Email Customer Support
  • Access to exclusive Sutro’s Cabana Club Facebook Group
  • Lifetime warranty

Why not give Sutro a try so that you can have crystal clear water that’s always ready for a swim.

Buy a Sutro Smart Pool Monitor

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