WaterGuru: pool monitor for a country where average IQ is falling

Average American IQ is falling (The Hill; note that this cannot be due to a massive increase in low-skill immigration from countries with a low average IQ because #Science proves that IQ is not heritable). Those who get jobs doing pool maintenance, a process that involves some chemistry, tend not to be the best and brightest within a labor pool whose overall trend is away from high intelligence.

We recently switched pool maintenance companies because our old one wasn’t answering texts and emails regarding how to recover from a coconut assault on the pool heater (cracked case; heater still works). To make sure that the new company was doing a good job, I invested in a WaterGuru Sense S2 that sits quietly in the skimmer:

Instead of buying two months of test strips from Amazon for $12 and suffering the indignity of interrupting your TV watching and Xbox-playing to put a strip in the water you pay these folks a higher price/test every day for the rest of your pool’s life. In return, you get notifications and recommendations from the app.

The new pool maintenance company sent out a young man who had only just gotten out of training. He was seemingly unable to keep the pH anywhere near where the WaterGuru thought it should be. After a few weeks, I asked him what his target was. He said that he was trying to keep the pH “above 8”. I said “Your test kit maxes out at 8. How can you target a value that is above the maximum range for your test?” This question hadn’t occurred to him, but he agreed to add some acid because the app said to do so. I asked “why does the acid bottle say the pH should be between 7.2 and 7.6?” He responded “I was trained to keep it above 8.” (I later talked to his managers who said, ‘He must have misunderstood the question because he is aware that 7.4-7.6 is the ideal range.”) If you’re trying to maintain the pool chemistry yourself, the app gives helpful recommendations and pitches for supplies to order:

The next dramatic event was that the pool monitor reported a normal level of chlorine (4.2 ppm of “free chlorine”) and the kid, based on his own test kit and I’m not sure what target chlorine level, decided to dump a bottle of chlorine into the pool (which has a continuous chlorine generator so it shouldn’t ever need a bottle). The monitor went nuts the next day, reporting chlorine at 10 ppm and only because that’s the top of its test range (an indoor pool with more than 5 ppm is illegal in Florida; the app says a good target is 3 ppm). A detail page showed the actual measurement at 13.5 ppm (24 hours after the chlorine addition). I bought some test strips at the local pool supply place and the chlorine level was somewhere between 10 and 20 ppm. I turned off the chlorine generator and the numbers came down gradually.

If you’ve created a society where humans aren’t smart it is nice to have robots like this one! (Once the chemistry is under control it is possible to reduce the frequency of the tests in order to save on the 28-day cartridges.)


48 thoughts on “WaterGuru: pool monitor for a country where average IQ is falling

  1. Readers demand that the chemical situation in the pool is resolved by the next solar eclipse as this is the ideal viewing location.

  2. I’m not trying to be a jerk here, but you went to MIT, shouldn’t you be able to manage your pool’s chemistry better than some schlub without much trouble? The pool I grew up going to was often maintained by (admittedly college-bound) high school lifeguards, some of whom probably hadn’t had high school chemistry yet. The STEM dads in town would manage their private pools more intensively, drawing the chlorine down for pool parties, up for algae blooms or other contamination, taking action for clarity, etc. and actually seemed to enjoy it. (Chemistry is fun)
    That does look like a nifty gadget, though.

    • Nobody that I’ve met in Florida manages his/her/zir/their own pool. Everyone pays $100-150/month for a “pool guy” (I’ve never seen anyone who appears to identify as “female” doing this job. Sexism? The people in the comfortable office jobs at pool maintenance companies often have female-associated names.)

      My neighbor tried to do it himself for a year. He was accepted to a PhD program in #Science, but decided to become a physician instead due to getting married and having to move to where his wife was being trained. So he’s way ahead of me in chemistry. He said it was a disaster and that he seldom got it right.

      (Home Depot does sell everything that a consumer would need to maintain a pool him/her/zir/theirself. Ergo, I’m sure that it happens, but I haven’t met anyone who is attempting this. Home Depot actually doesn’t sell some of the standard stuff that you’d need, e.g., liquid bottled acid.)

    • I think you have a point. My father (CPA) and middle-school / high-school me were able to manage a pool. We had a little home kit with some reagent drops and would routinely take a glass pop/soda bottle to a nearby retail store that adjoined a frozen yogurt franchise.

      The difficult part was applying the cover in winter, pumping water and removing oak leaves throughout the winter, and vacuuming oak leaves in the summer. I think once we had “mustard alge” that required some other harsh chemical and a steel brush.

      But the routine chemical management during the summer was really not that bad, and it sounds like you already know what you need to know (pH, total chlorine, and free chlorine).

    • FB: Most of what a pool owner pays for is not the chemistry management but cleaning. The “pool guy” vacuums and rakes the pool to get out all of the leaves. He will clean the cartridge filter. He will remove leaves from the skimmer. So most of what you’re paying for is the cleaning service and not the chemistry test and acid pour. A homeowner in the Northeast can maybe keep that up for two months, which is the entire backyard swimming season in Maskachusetts. But could he/she/ze/they do it every week for 52 weeks/year? Remember that the pool has to look perfect because it is the central visual feature in the backyard. It can’t have any leaves floating on the top or resting on the bottom.

    • You are right about the vacuuming. My main takeaway from the experience was “don’t own a pool,” so I see why you’d want to hire it out.

      Maybe tell them to ONLY do the vacuuming and you’ll take care of the chemistry yourself.

    • I have to agree, this does seem to be a bit overwrought for the particular task at hand. We had a large pool by Northeast standards: L shape, 20×40, with 16×10 second section, propane heat, and so on. For a long time, we obtained satisfactory results with a robotic cleaner, though I had to replace a few parts on it over the years. We used to pay for close/open, which was mostly just time & physical labor avoidance. Later on, due somewhat to the labor issues Phil describes, I started doing all of it myself: open/close, chemicals, daily cleaning, etc. Cleaning was a nice way to warm up after a day in a ~68 degree office building.

      The worst of it was removing the algae in the Spring, and getting the scuba guy to fix an occasional liner rip (gunnite pools were less common in our area). The algae took a few
      rounds of shock to remove, with attendant flushing of filter, and the rips meant calling in
      the Navy Seal team to patch the liner. I had my own scuba gear, but not the patch superpower.

      Maybe this drama makes for entertaining blog entry, but I never found managing the pool to be difficult at all. Perhaps the longer seasons in warmer climates make this all 500% more work to manage?

      Look on the bright side of it: I had family that lived in the south and would find (poisonous) snakes and spiders in the filter basket. You learn to pay attention when grabbing the basket to empty it.

    • NaPG: Of course, there is nothing that would stop a homeowner from doing the weekly cleaning of a 14,000 gallon pool. But at the same time, there is nothing that would stop a homeowner from doing the weekly cleaning of a 2,500-square-foot house. Yet we seldom see an upper-middle-class American without a housecleaner (usually a noble immigrant who is enriching our society and who is not in any way lowering wages for native-born Americans who might want to get paid to do this job).

    • I had a colleague once who visited Naples, and on a whim put a $4M bid in on what he called “the world looking home on the block, falling apart, car up on blocks”. Said tongue in cheek, and of course, the house was gorgeous in absolute standards, but not as much judged by adjacent properties. The bid was accepted, to his surprise.

      Anyways, depending on how you define upper middle class, but certainly having owned houses in the 3000-4500 sq ft range, we never had house cleaners. I totally get the my-pay-rate vs trade-pay-rate thing, but still pick and choose when I want to pick up a hammer, wire a house, etc. So now you know one more person who doesn’t have a house cleaner.

      Anyways, I wasn’t being critical in the overwrought comment, after all, I came for Travels With Samantha, the early flight experiences of Phil (Alaska), especially the dog stories, Alex (RIP!!!), and the more “rich person” problems of Naples Greenspun. Don’t ever change. But, pick up a hammer once in a while, you might enjoy it.

    • A hammer? This is Florida and we’re all about the Tapcons! I spend a huge amount of time doing hands-on house maintenance. We had 20-year-old built-in closet shelves that were sagging down from their studs-attached brackets due to (German Hafele-brand) hardware stripping out from the particle board. So I went on a huge odyssey of jacking these up with hydraulic jacks, putting 2x4s underneath that were toggle-bolted into the metal studs (used a fancy Bosch studfinder: https://amzn.to/44JtiZR ) or Tapconned into concrete exterior walls. That’s the kind of project that is tough to find someone to do (a “closet company” would just rip out all of the closets and start over) so I used the time that I save from not having to do all of the pool cleaning to do stuff like that.

      Speaking of Tapcons, there are no basements here so it is critical to optimize every cubic foot of space in the garage. That means ordering custom-size wire shelves that are 8′ high and then Tapconning them to the concrete wall so that they can’t be pulled over and crash down on a car or a person.

      There are also plenty of homeowner tasks that aren’t challenging enough for a contractor but that aren’t easy to pay someone to do. Clearing debris from the Bosch dishwasher impeller. Dealing with slightly broken toilets (e.g., new flapper required). Replacing the cracked lens on the light that is part of the garage door opener.

      We have plenty of neighbors with comprehensive tool chests, engineering degrees, and mad mechanical skilz… they all have weekly pool cleaning service.

    • Ha! I knew it. You are our leader, Phil!

      From reading the blog here, I see that you’re being pressured to host a eclipse party in a few years, so please get to work putting together a solar telescope with suitable camera system, and hopefully a modern wasm remove app vs Ruby-on-rails for us folks who aren’t allowed into the free territory of FL 🙂


      You know, come to think of it, you have the means to measure pool chemistry already, so a great kids-n-dad project would be a pool bot that introduces appropriate chemicals in a feedback loop. Boys, let’s look at PID controllers today, step 1, …

  3. STEM is often badly taught at the high school level. I think what is missing is not enough history behind the uses of Math and also Chemistry. What everyday problems were the experimenters/inventors/mathematicians trying to solve? Everything is simply taught without any context. eg. Calculus without discussing Kepler and the wine barrels story.


    Chemistry and Organic Chemistry are taught as such dry subjects, and the professors are usually dull as well. Also the custom of using STEM classes to weed out the people who have no business going in to medicine, while makes sense from a numbers game, is just a disservice to education in general. The material should be taught in more accessible way for the general population’s benefit.

  4. It’s basically Universal Basic Income, but for beer! Didn’t you have a similar idea about McDonald’s one time? (although why the bartender in this case needs to be a nurse is not explained in the article)

  5. A common theme here, Phil goes out and buy something really expensive, something most people could only dream of, here a pool, elsewhere an exotic stove, refrigerator, some kind of special windows, etc. , the purchase does not work as expected/has complications and Phil needs to spend time dealing with dimwits without a PhD in engineering from MIT to resolve the problem. Most of us who want to swim just use the Y or its equivalent and let the Y deal with these issues. The $150 per month dealing with some pool maintenance company is about the cost of an average Y membership.

    • jdc: We didn’t buy a pool. We bought a single-family house in Florida and a pool is a standard backyard item. Nearly everyone here has access to a pool at home. The apartment- or condo-dweller has the building’s pool. The homeowner has the backyard pool. The owner of a townhouse has the HOA’s pool. Your theory is that the intelligent Floridian family buys a house and then immediately pays to have the pool filled in and turned into grass? Or stays in an apartment and lets the landlord deal with the pool? (I heartily agree with you on that one!)

    • There is a good public outdoor 50-meter pool nearby: https://discover.pbcgov.org/parks/Aquatics/North-County.aspx

      But the 50-meter exercise pool isn’t a substitute for a backyard pool, which you might use with your family and friends for 30-60 minutes every day and the pool also serves as a decorative feature that you can enjoy even when you’re inside (the shimmering blue water amidst the pavers or tiles). Maybe if they built a swim-up bar in their 50-meter pool…

      (but probably not; I like to play classical music when I’m enjoying the yard and pool (Klipsch wall-mounted outdoor speakers driven by a Yamaha receiver inside; all of the wiring was already there, though one of the two old speakers was dead). My musical taste isn’t shared by anyone else. So if the 50-meter pool nearby got turned into a Royal Caribbean CocoCay-style environment I still wouldn’t like it as much as our backyard pool because I would rather listen to my own music than whatever Royal Caribbean picks)

  6. Is your pool refilled from community water pipe or couple times per year and has close water cleaning cycle or does your pool have a separate well? I dread pools that are filled by water cisterns and have close water cleaning cycles. It is not that expensive to drill a well for the pool if communal water pipe is off limits. Is it a heated pool? In case you want to swim in cold 70 degrees Florida winter nights.

    • perplexed: the pool is filled by me from a hose and/or by God from the sky. So it gets domestic water (Town of Jupiter) or rain water. And of course it came with a heater (400,000 BTUs fed by natural gas, which is plenty for 14,000 gallons), though the top case is cracked after a coconut assault. When the heater completely dies, we have just enough power out there (60 amps at 240V) to run a heat pump that will also be able to chill the pool in the hottest part of the summer.

  7. Now I’m genuinely curious about your musical tastes, Phil. I love classical music as well, plus a lot of other genres.

    BTW I used to clean the pool at a hotel where I stayed for a quite a long time, because I liked to swim in it and they never cleaned it. It was hard work! Pushing a net through the water, with terrible leverage (a long handle) was harder than it looks.

    • John: for hanging out at the pool, I’ve listened to piano music and pre-piano music on the piano (Handel, Bach). The kids demand Imagine Dragons, Led Zeppelin, and some other rock bands. Within what people call “classical” I like everything from Bach to Stravinsky. I had thousands of LP records, nearly all classical, before the move to Florida (donated them to archive.org).

  8. I maintain my pool myself not because I terribly enjoy it but the aggravation of dealing with “pool guys” is much worth. While the process is tedious, it’s not terribly complicated.

    Early in my career as a pool guy substitute, I discovered that both strips and pool supply stores measure chemical levels quite badly, but you can get reliable result with a chemical kit (19th century technology).

    I use the kit to test levels of FC and pH once a week. It takes about 5 minutes. Then I adjust the salt water chlorinator up/down and add some hydrochloric acid(if needed). Maybe another 5 minutes. Once a month or so, I check the CYA level.

    Your FC level looks borderline low which may lead to algae infestation. It’s hard to say without knowing the CYA level:

    I considered WaterGuru as a replacement for the test kit, but read contradictory opinions as to its readings correctness, so decided against it.

    To clean the pool I use an underwater Rumba cousin once a week.

    • Ivan: As of yesterday, we have 4.9 free chlorine (people say 3-5 should be the target around here), 7.7 pH, 68 CYA, 76 total alkalinity, and 235 calcium hardness (flagged by WaterGuru as “low”, but just south of the border of “normal” (maybe it can walk across the border and claim asylum?)).

      I seriously doubt that WaterGuru is more accurate than strips. The “pool guys” all use the Taylor liquid tests. I’ve seen the pool vacuuming robots, but that’s yet another machine to maintain, store, empty out, etc.

    • Actually, if you look at the chart I provided, it the FC level should be between 5-10 for the given CYA level. 4.9 is an invitation for algae. I keep it at 7-8 with CYA at 70.

      I use Taylor myself. It’s as accurate as you can get. The CYA level determination is the trickiest but I do it only if the SWG starts falling behind and the FC level goes down.The CYA level goes down if you or rain dilute your pool with fresh water.

      The robot has been reliable for 4.5 years. It runs for about two hours, and then you just empty its bucket of debris.

    • Ivan: As of today, the free chlorine is up to 5.6. That’s within the target range from your chart, I think, though slightly low. I’ve heard that one has to increase the salt generator output as the days get hotter, right?

    • Leaving pool open in the sun or actually using it brings down chlorine level. So essentially for salt water pill you build up some chlorine during the night, then use it up during the day.
      By the end of heavy use it might hit 0, it’s ok as long as generator is running and will replenish it.

      You need to adjust the generator if in the morning you get a number which is out of range.

    • It’s not so much heat as UV radiation that destroys chlorine. If a hot day is cloudy, then there’s less chlorine loss than on a sunny similarly hot day.

      CYA somewhat slows chlorine loss but also reduces its efficiency. That’s why you need higher Cl level with a higher CYA level (see the chart reference above).

      You can increase the SWG output by either pushing a button on it to make it run more frequently during an hour, or the total time it runs during a day by adjusting a timer that controls the pump/SWG.

      In my setup, I run the pump 24×7 and the timer controls only the SWG.

    • Ivan: You’ll be pleased to learn that #Science says free chlorine should be only 1-4 ppm. https://www.cdc.gov/healthy-swimming/safety/what-you-can-do-to-stay-healthy-in-swimming-pools.html

      The CDC also reminds readers of the web page “Don’t pee or poop in the water.”

      #Science changes as necessary so #Science also tells us “Maintain free chlorine levels continuously between 1–3 parts per million.” –https://www.cdc.gov/healthy-swimming/toolkit/operating-public-pools-hot-tubs-and-splash-pads.html

      Why do you need 7 ppm when Science says that 1 is enough and 3 ppm is way more than enough?

    • “Why do you need 7 ppm when Science says that 1 is enough and 3 ppm is way more than enough?”

      Well, because I got algae starting when my Cl level fell to 3 ppm and had to “shock” the pool with 15 ppm for 48 hours to kill it.

      Since then, I’ve kept the level at 7-8 ppm.

    • Reality is that maintaining 3 ppm FC through the day on the dot is nearly impossible – see sun and use. I shoot for 5+ in the morning and hope it’s enough for the day. It’s below 10 I basically don’t bother – it’s ok for swimming.

  9. Muriatic acid? HOW BACKWARD IS THAT NAME?

    Muriatic acid? That name for Hydrochloric acid went out of use in Britain about two generations ago. Certainly out of use by the time I started Science at school in 1944. Astonished to see it here!

  10. Cool pool by using fan spray airater hooked to your circulator pump. Run it at night for a few hours. Evaporation cools the water.

    Buy and install a robot pool cleaner to vacuum up leaves and debree from the pool each day. Hook it to timer and run it a few haurs each evening.

    As you have found pool maintenance people are terrible at taking care of pools. The staff are mostly young kids with no brains and no desire to work. No immigrants are in that business due to chemestry and chemical license requirments. So no long term people are in this business who learn how to take care of pools and want to do a good job

    Best solution is to get rid of your pool or buy a house without a pool. Or you can drain the pool and make a underground store room out of the hole in your back yard.

    Second best solution is maintain the chemistry yourself and teach your kids to brush it and clean the baskets every 2-3 days. When the kids get older and sort of responsible you can teach them chemistry and how to use the pool chemicals.

    Third best solution is hire a pool person and live with the poor results. Probably they will quit at least every 1-2 years and goof up the pool at least once a year. And they will quit when you are out of town and goof up everything.

    • btenny: Thanks. If these aerators cool by evaporation, doesn’t that mean you’re going to have to refill the pool with fresh water more frequently? Maybe not a huge problem in the Florida summer given the thunderstorms that we have.

  11. In Seattle I’m managing pool myself because it will be more managing of pool guys than to actually manage the fucking pool itself.

    Just last week my regular contractor said that he is not gonna be able to do the job he signed up for before (sand filter maintenance and heater replacement) – guess what, I’m replacing sand myself and bypassing heater for now.

    How do you like your new gadget? Looks very promising. I’m going to order one myself, if it measures reliably, it will simplify my life a lot.

    • SK: I do like it and I think the chemistry will only get better as they come up with new cassettes. A pool is a living breathing chemical thing so having a daily message is great. It also does continuous measurements of temperature so it would be possible to see the effect of a cover, for example, or the aerator that btenny mentions.

  12. Pools in Arizona have auto fill water valves. I guess the aerator uses more water. The extra water is not a big issue out here and with auto fill and auto chloridation and auto sweeper and cleaner you can go 3 days or more between checking pool. TBD how good all this stuff works in humid Florida.

    In Arizona our thunder storms are usually accompanied by blowing dust and wind and lots of leaves and curd. This fills the pool with dirt and crud and turns the water brown. Then the brown water turns green with algie in 12-24 hours. The only fix for this is super chloridation and brushing down the pool walls and emptying the baskets and running the filter extra cycles. This happens about once a week for most of the summer. It is a 1real PIA…..

    IF you have a pool person they might not come for 3-10 days after one of these storms. This gives the algie and dirt in the pool time to grow more and and get attached to the pool walls. This is real bad news and may not be recoverable without draining half or more of the water. Plus the pool walls can be stained perminently……

    • Newer pools in Florida also have auto-fill. We will probably retrofit that to our pool when it is time to renovate the tile and plaster (a $25,000 project every 20 years). It’s probably no more than $2,500 for the auto-fill, including some digging and installing a backflow preventer near the spigot.

  13. This reminds me of the days when we use to take a dip in a river or lake to cool off. No checks for pH, CYA, leaves, or dead-bodies!

    • paddy: Sorry for not specifying. As noted in another comment, the pool is the core of Florida backyard decoration. It has to look great even in the coldest week of January when nobody would think of using it. Thus, the pool company has to come every week to clean out any unsightly debris that might have blown in, e.g., leaves. The $150/month also includes most chemicals and all chemical tests, but you’re paying primarily for cleaning. (You’re also expected to have landscapers every week to cut back whatever has grown wild (which is pretty much everything in Florida, except for orchids), collect leaves, etc. The HOA fee typically covers the weekly landscapers for the front yard and that is done on a community-wide basis. The Yankee Shabby aesthetic that prevails in New England isn’t socially acceptable in Florida.)

      (People who have pools that are completely covered in screen enclosures could perhaps get away with less frequent cleanings, but nobody in our neighborhood has one of those monster enclosures.)

  14. The pool guy who came to my Airbnb in Naples was in his twenties, muscular, very good looking and nice to look at, like in the movies. I thought pool guy was a standard trope for gigilo or boy toy.

Leave a Reply

Your email address will not be published. Required fields are marked *