Review: Crystal Water Monitor
Our Crystal Water Monitor next to the Stock Tank Pool
When we put in our Stock Tank Pool in 2020, I didn't know much about maintaining a swimming pool. We had a swimming pool at our home in Los Angeles, but we also had a pool guy who came and managed everything. And because I wanted to be as ecologically-responsible – maintaining the pool water rather than draining it all the time – I needed to learn about pool water chemistry. I did. And I learned that having a pool monitor is one of the best investments I could make as a busy mom and writer who didn't want to spend a ton of time keeping my pool clean.
Over the last few years I have had three different pool monitors, and I will tell you that the Crystal Water Monitor is by far the best and easiest to use. It is worth every penny – even for something small like a stock tank pool or a spa.
“Full Disclosure: Crystal Water Monitor sent me their product to try. They did not compensate me for this review, however. And all opinions are my own.”
What is the Crystal Water Monitor?
The Crystal Water Monitor is a smart water quality monitor designed to help pool and spa owners maintain ideal water conditions. It provides real-time insights into measurements that affect water safety and comfort. No more guessing about what to add and when. It just tells you what to do!
Why is the Crystal Water Monitor the best monitor I have tried?
There are really three reasons:
No cartridges: you don't have chemical cartridges to replace every few weeks. This is lower in waste and lower in cost than some other monitoring systems.
Small In-water Device: with a stock tank pool, size really matters. And a big monitor bobbing around is annoying. The Crystal Water Monitor is so small we hardly know it is there.
Accurate Recommendations: with continuous monitoring, when the water needs treatment, the monitor's app provides simple treatment recommendations including details on how much of each chemical you'll need to add.
With my last water monitor, I was adding chemicals more frequently and in larger quantities. Then the water balance would be off, and I would need to add even more chemicals to bring it back into balance. Honestly, I don't think it was well-calibrated for a small body of water like a stock tank pool.
I have had NONE of these issues over a whole summer using the Crystal Water Monitor. And when I check the pool chemistry using a dip strip, the results are right on.
DIY Stock Tank Pool Guide
It’s easy. It’s cheap. And it is one of my favorite projects. You’ll find all of the details here!
The monitor probe in the pool. It practically disappears!
What does it measure in pools and spas?
The device tracks several important water quality indicators, including:
pH levels
Water temperature
Chlorine (ORP or Free Chlorine, depending on model)
Salinity (for saltwater pools)
Why is monitoring water quality important in pools and spas?
Maintaining balanced water prevents:
Skin and eye irritation
Bacterial growth
Damage to pool/spa equipment
Staining and scaling
Wasting money on unnecessary chemicals
Wasting water on complete water changes
I have seen many Stock Tank Pool owners who brag about not treating their pools. They just drain them once each week and refill with fresh water. But at 500+ gallons per pool, that is irresponsible and wasteful. Stock Tank Pools can be maintained with either chlorine or salt water. I use chlorine so that when I do drain and refresh the water – usually once mid-summer and then at the end of the season – I can use the water in my garden (once the chlorine levels are low enough).
Does the Crystal Water Monitor work with hot tubs?
Absolutely! It works with both pools and spas, including hot tubs up to 104°F (40°C). When you set up the app, you create a profile for your pool with details including the size, chlorine or salt water, and the chemicals you are already using.
How much does it cost, and is there a subscription fee?
At this writing, the first year of monitoring is included with the monitor. From then on the cost is $99 per year which includes support and service as well as replacement of sensors and warranty coverage.
The cost for the monitor itself varies depending on whether you're using chlorine/bromine or salt water. Be sure to order the correct monitor for your pool.
Does it work with saltwater pools?
Yes. The Crystal Water Monitor supports chlorine, bromine, and saltwater chlorination systems. Just select the appropriate water type during purchase and set up. We have a chlorine pool, so I have not tested this in a salt water setting.
More FAQs
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Yes. The Crystal Water Monitor has two pieces which are connected by a cable. The sensor drops into the pool and is almost completely unnoticeable. The monitor itself can sit by the side of the pool. I have ours attached to a small table. It's unobtrusive and so simple.
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Yes. The app will alert you when key parameters go out of range and provide simple guidance, like:
“Add Slow-Release Chlorine”
“Time to Shock”
This helps you avoid guesswork and maintain safe water conditions.
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No. You add the chemicals you are already using to your profile, and the app gives you appropriate dosing instructions for each one.
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Yes! You can view your pool or spa’s water quality in real time through the mobile app, whether you're home or away. Of course, it won't add anything for you. You'll need someone to do the actual maintenance, but you can monitor while you are away.
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Yes. The app sends instant push notifications when your pool needs attention.
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It runs on batteries. The first unit I received was burning through batteries every week or two. I contacted customer service who said that was not normal. They sent me a new unit which has lasted nearly two months on a set of batteries. Much better!
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It significantly reduces the need for manual testing but does not entirely eliminate it. I have to do a manual test about once per month to calibrate the monitor, and if the water quality is really off, sometimes more testing is necessary.
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The app includes step-by-step calibration instructions and prompts you to run a test when needed. Calibration solutions are available from Crystal Water or pool supply stores.
Having used two other water monitor solutions, I can tell you that the technology just gets better and better. And the Crystal Water Monitor is, by far, the best water monitor I have used to date. Our pool has been clean and safe all summer long with very little effort.
Questions? Don't be afraid to ask!