From the time I first bought a ten-inch deep inflatable splashing pool, my children have loved swimming in the summer. I started learning about pool chemistry a long, long time ago while keeping above-ground pools sparkling. One day, I needed some chlorinator in a hurry and a Big Chain Pool Supply (BCPS) store was half a mile away. I usually avoided the store, because their prices were astronomical and their salespeople were pushy, but it was close and small and convenient.
I walked in the store, grabbed a box with two gallons of 10% sodium hypochlorite (“chlorine liquid”) and proceeded to the checkout. I started getting the third degree.
“What are you getting this for? Do you know you could hurt your family and destroy your pool? Have you had your pool water professionally analyzed.”
“Are you going to sell it to me or not?”
The man took my money and I started for the door, and two more salespeople left the counter and started racing me for the door. One beat me there, yelling threats about how I was going to summon Cthulhu or some such, and blocked the door. I mimed throwing the box at him, and when he jumped out of the way I dashed through the door. I thought I was free, until he followed me to my car. Now he was practically begging me to agree to return with a sample of my pool water. In an enema bag, maybe I thought, but just silently got in my car and left. Never to return.
My children were outgrowing above-ground pools. I tried to figure out how to add a pool to my house, but it just wouldn’t work (there were too many beautiful redwood trees nearby). When I decided I needed to move for other reasons, we looked for a house with a pool. We found one in a wonderful neighborhood and bought it, though the pool was scummy and green. You could barely see the bottom. At one point a flock of ducks landed in it.
I was still working at the time — a lot, as the covid crisis was in full swing. We hired a pool professional to get everything straightened out, but he was still recommending a new chemical for every pool symptom. Once I retired, I took over pool care myself and still refused to visit BCPS. I was a physician and in my former life as an electronic systems designer I had done some work with industrial-scale drinking water processing.
salt
I decided to go with a saltwater chlorination system. We replaced the existing, broken down and ancient pump and filter with an oversize filter and a variable-speed pump. We added the saltwater cell.
A saltwater chlorinator is different than trying to maintain a saltwater pool that’s as salty as ocean water. In this system, the water has about one-tenth the level of salt as seawater (about 3,000 parts per million). It tastes only slightly salty, and doesn’t corrode everything in sight as happens in a marine environment. It also won’t kill most plants if they happen to get watered with it. Most people find the mildly salty water somewhat more pleasant than a regular chlorine-added pool. Instead, the chlorinator uses electricity to generate free chloride ions from the salt. It doesn’t deplete the salt (measurably, anyway) so once you add the initial salt (about 500 lbs for our pool!) you don’t have to keep adding it except when it gets diluted from replacing the water that gets splashed out. Salt is, of course, not toxic at these levels and there are no bottles of dangerous sodium hypochlorite hanging around.
acid
Unfortunately, one side effect of the chlorination reaction is that it generates hydroxides, which raise the pH of the water. You have to correct this by adding hydrochloric (“muriatic”) acid, just as you would with any pool but somewhat more often. So there are still bottles of dangerous chemicals around, but not nearly as many. In addition, for all that hydrochloric acid is horribly corrosive, it is not carcinogenic or mutagenic and it doesn’t have long-term deleterious effects on living things. It doesn’t hang around in the environment or contaminate the soil, and the processes by which it is created aren’t environmentally horrible.
anything else?
In a word, no. I run my pool filter longer than I absolutely have to in order to keep the chloride level up without adding a stabilizer like cyanuric acid. That’s trading energy for atoms, but it also is one less chemical to which I am exposing my children, HA, Luna the Big Dog, and myself.
There are dozens (hundreds?) of pool care chemicals, all of which the sellers (BCPS) will claim are non-toxic and environmentally friendly. I don’t trust them, and I don’t have the time to do the research to convince myself of their benignity. Salt and acid, I know, are simple, cheap, and safe and they keep my pool perfectly crystal-clear.
Are there downsides to this minimalist approach? Well, it requires some patience. After a good storm the pool will stay cloudy for a week or so. An anti-flocculant would work faster, but would be more $$$ and chemical exposure. The not ideal levels of alkalinity means the chlorinator has to work a bit harder, but again that’s in exchange for fewer $$$ and fewer chemicals. All in all, I’d say the tradeoffs are worth it.
Maybe I’ve saved enough money to get it re-plastered.
—2p