Automatic sanitizers are safe and convenient.
They save homeowners from having to hand-feed chlorine or bromine into their pools. And they’re a significant time-saver for service technicians.
But improper installation and maintenance actually can do more harm than good.
For optimal performance, keep the factors on the following pages in mind.
1. Monitor the system to find the right output.
Chemical feeders, while user-friendly, are not a catch-all.
“They’re controllable with a valve, but there’s nobody there to tell the system to up the dosage if there’s a higher demand,” says Ed Penfield, president of Aqua Island Technologies in Bellingham, Wash.
Regardless of the type of sanitizer, you must observe its output and how it affects the water’s sanitization.
On salt systems, check the chlorine levels and adjust accordingly. If even the lowest setting is too much, you may have to get creative.
Bill Peck programs his salt systems to run only part of the time the circulation system is on. He cites another pool that had one primary user and was run year ’round. This vessel didn’t require as high a chlorine residual.
“We have to hook it up to a separate control so it only runs half the time,” says the owner of San Diego-based Peck Pool Services. He adds that the customer appreciates getting extra mileage out of the electrolytic cell.
Even on the lowest setting, erosion chlorine feeders may introduce too much chlorine into the water. Simply lower the dosage and the chlorine concentration by adding fewer tablets.
“If I filled the whole canister, it would be getting more of those tablets wet and I would get a higher level in there, which would be even [harder] to control,” Penfield says.
So he determines how many pills will sustain the pool without overchlorinating until his next scheduled visit.
“Even if they’re on large bodies of water, you learn to not fill them all the way up with your sanitizer tablets,” Penfield says. “You know you have enough tablets to last for a week — just don’t fill the thing [to the top].”
2. On salt, watch where you place the spa overflow line.
For pool/spa combinations, instruc-tions from the salt chlorinator’s manufacturer should indicate where to place the unit relative to the spa bypass.
Many installers place the bypass after the salt unit. Peck prefers to put it before. Otherwise, any calcium flakes that are kicked out of the chlorine generator from self-cleaning will enter the spa, which is not equipped with an automatic cleaner to remove them.
“[The flakes] land on the steps or go in the spa and sit there,” he says. “If your water chemistry isn’t good and you’re not taking care of the pool, they sit there until they stick.
“The proper way to do it is to have the bypass tap in before the cell, and then you don’t have the problem,” he notes.
3. Don’t oversize the pump.
The slogan “small-pump-large-piping” traditionally is used when discussing hydraulics. But it applies here, too.
“When they put a big pump on, people don’t want to run a [salt chlorine generator] long enough to keep the pool sanitized
because of the electricity bill,” Peck says. “Chlorine generators are time-dependent. On our average residential pool, the chlorine generator has to run six to 10 hours a day to make enough chlorine in my area in the warm weather, especially if it’s a bigger pool.”
Bottom line: Install the smallest pump possible, or a two-speed or variable-speed version, so the pool can run as long as necessary without emptying the client’s wallet.
4. Don’t forget the time clock in public settings.
In a commercial setting, an electric chlorine feeder should be plugged into a switch or time clock so it turns off with the circulation system, Peck says, even if the pool is expected to run constantly.
“Even if they run it 24 hours, sometimes things get shut down for one reason or another,” he says. “I’m working on a project where they replastered the spa and wanted to turn the [circulation system] off for a couple of days. You have to remember to unplug the chemical pump because it’s going to keep pumping chemicals. So it’s very bad to not have it interlocked with the filter pump.
“Whatever switch turns off the pump had better turn off the chemical feeder, too,” he stresses. Peck adds that occasionally, he’ll see a news story about a situation where no water is flowing and the feeder is pumping chemicals. “The chlorine and acid are mixing in the pipe and the fumes come out, and they have to evacuate everybody,” he says.
Be sure to follow local codes, some of which don’t allow time clocks, Peck adds. Switches and time clocks are particularly helpful in reconciling codes with the pool’s individual sanitizing needs. Some codes require a particular-sized chlorine pump, regardless of the pool’s actual needs.
“This is something people don’t understand,” Peck says. “They put [the chlorine pump] on, it passes inspection, then it overchlorinates the pool. So what happens then is, they turn it off and don’t use it. You find [the pump] buried in the corner under a foot of diatomaceous earth because they didn’t figure out how to make it work right.
“When it’s oversized, then you have to put it on a time clock so it doesn’t run all the time,” he says. “Usually, the pool’s only open half the day, so [the chlorine feeder] doesn’t have to run all day.”
Of course, if the feeder is attached to an ORP controller, you should be covered.
5. Don’t leave salt alone.
The industry has abandoned the myth that salt chlorinators will do everything but physically sweep the pool. Unfortunately, many consumers haven’t.
As a result, new techs should be wary of consumers who claim a salt system means nobody needs to watch the pH, alkalinity and other factors affecting water quality.
These units produce liquid chlorine, which inherently causes pH levels to jump. So techs still must carefully monitor pH, along with alkalinity.
6. Consider the heater.
Chlorine feeders and salt chlorine generators must be placed downstream of the heater. Otherwise, the concentrated chlorine-and-water solution will damage the heating element as it passes through.
With tablet feeders, install a chemical-resistant check valve after the heater and before any type of chemical injection feed or in-line chemical generator.
“The tablets are very acidic, and when the system is turned off, the tablets sit there and dissolve, and the high concentration of chlorine and the low pH can migrate backward and get into the heater,” says Bob Wilkinson, service manager at Swim Chem in Sacramento, Calif.
The feeder should be installed a safe distance from the heater — ideally, 2 to 3 feet — or 1 foot at minimum, Wilkinson suggests.
7. Don’t neglect the probes.
If the system relies on probes to monitor the sanitizer, regardless of which type of device you have, those will have to be cleaned.
“If [pool owners are] going to go with a unit that regulates the amount of feed based on sensory data, they have to keep those sensors cleaned and replaced on a regular basis,” says Michael Orr, owner of Michael Orr Solar in Manteca, Calif.
On granular dichlor units, he says, place the probe in a solution that’s 10:1 parts water to muriatic acid for 15 to 20 minutes. Then rinse. This removes any scaling that may have formed.
To keep the probes as clean as possible, consider using a sequestering agent in the pool water.
“This is especially important on salt systems, where the plates and electrolytic cell will scale up over time,” Orr says. “By keeping a sequestering agent in the water, you will minimize the scaling and get a longer run before you need to clean the plates.”
Ultraviolet systems, by contrast, work with a quartz sleeve.
“UV light is housed in a dry atmosphere, and the quartz sleeve is a round tube in most instances,” Penfield says.
If it’s not clean and clear, the light can’t shine through, and it won’t remove the passing pathogens.
To remove scaling and buildup, Penfield cleans these at least once a year, either by hand or using the internal wiper that comes with the unit.
“They’re like donuts that are wrapped around the quartz sleeve,” he says. “So when you pull the rod out and push it back out again, you’ve already wiped your quartz sleeve.”