Bromine
What it is: Pool suppliers sometimes suggest bromine
as a substitute for chlorine. It can be an acceptable alternative for
those with allergic reactions to chlorine, although that’s not
guaranteed since bromine is also in the same halogen chemical family.
Aquatic specialist Alison Osinski believes 5% of the population has an
allergy to chlorine.
How it works: Bromine does a
fine job as a sanitizer, but it doesn’t oxidize as well as chlorine.
Most homeowners rely on a hybrid version known as BCDMH tablets that are
typically 66% bromine and 27% chlorine to tackle that job. Some people
opt for a two-step process of combining bromine salt extracted from
seawater with potassium peroxymonosulfate (a.k.a. oxygen shock) in the
pool to create that same sanitizing/oxidizing power.
Pros/Cons:
Bromine remains stable at high temperatures, which is why many
technicians recommend it for spas more than swimming pools. It’s less
irritating on mucus membranes than its chlorine cousin, although it
still produces an odor. And if you use just bromine in the pool (not the
BCDMH compound), it leaves the water a dull green color that foams up
when you swim in it, because the oxidation process is weaker.
Cost:
It’s more expensive to operate a pool with bromine. Figure you could
spend up to twice as much as you would if you use chlorine only.
Ionizers
What it is: Ionizers rely on two dissimilar
metals—often copper (an algaecide) and silver (a sanitizer)—sent charged
into the water as the sanitizer. The oxidizer is missing, so you’ll
need a small amount of chlorine or bromine in the water to handle this
cleaning aspect.
How it works: An ionizer is a
device that uses a low-voltage DC current to send these two metals into
the water. The positive charge attracts bacteria, germs, and algae, and
the new, larger compounds they form are carried out in the filtration
system.
Pros/Cons: Like bromine, an ionizer
doesn’t irritate swimmers’ eyes and noses. It can substantially reduce
the amount of chlorine required. Chlorine and an ionizer work together
better than chlorine alone, says Osinski.
Yet, she still
considers ionizers a poor choice. For starters, you only reduce the
chlorine amount significantly if just a few people use the pool on a
regular basis, there are few plants and landscaping in the area, and
your air isn’t heavily polluted. High dirt levels are beyond what an
ionizer can fight on the sanitation side.
Also, ionizers depend
on moving water, so you must run the pool pump continuously to keep the
sanitizing action in place. And the increased levels of metal in the
water can stain the pool and turn swimmers’ hair and fingernail beds
green.
Cost: About $300 for an ionizer that
handles up to 40,000 gallons of water. Homeowners may need to replace
the metals in the system as often as once a swimming season, at an
average cost of $129. Also factor in the energy cost of running the pool
pump around the clock.
Ozonators
What it is: An ozonator is a machine that attaches
to the filtration plumbing line. It inserts ozone gas (an active form of
oxygen) into the pool to react with impurities in the water.
How it works:
There are two types of ozone generators: ultraviolet light and corona
discharge. In a UV light system, special low-pressure vapor lamps
installed on the water return line create ozone to kill pathogens as
they float by. Corona discharge generators rely on an electrical arc to
create ozone inside the generator. Again, this ozone kills pathogens in
the filtration system.
Pros/Cons: Ozone
generators can reduce chlorine usage up to 90%, and they use the same
amount of electricity as a 60-watt light bulb when the filter pump is
turned on, so the added energy demand is tiny.
Aquatic
consultants say ozonators combined with chlorine are extremely effective
as long as you circulate the water 24/7. One caveat: Ozonators run best
on dry air, so if you live in a humid climate, expect performance to
decline.
Cost: A typical ozone generator starts
at $600 to handle 7,000 gallons of water; $1,200 to cover 25,000
gallons. Take into account the expense of the pool pump running
continuously.
PHMB
What it is: There’s only one way to eliminate the
use of chlorine completely: Switch your pool to the chemical compound
PHMB, short for polyhexamethylene biguanide. Homeowners commonly know
PHMB by the Baquacil and SoftSwim brand names.
How it works:
PHMB disinfects by penetrating bacteria cell walls, causing them to
burst from within. It then wraps those particles in a heavy gel, which
sinks to the bottom of the pool, where the vacuum system sucks it up.
Pros/Cons:
PHMB doesn’t oxidize, so you’ll need to use hydrogen peroxide for this.
You’ll also need to use a separate algaecide and clean pool
filters—yes, even the sand ones—every four to six weeks.
PHMB is
kinder on swimmers’ skin and hair, easy on vinyl pool liners, and
doesn’t require as much attention as other chemicals to keep in balance.
However, because PHMB is incompatible with chlorine, you’ll need to
first drain the pool.
Once you’re back up and running, make sure
every bathing suit has been washed. Even traces of chlorine in suit
fibers will react with PHMB. The result of the reaction: a yellowish
vapor that’ll radiate from your bathing suit.
Cost: The cost for PHMB chemicals to maintain a 10,000-gallon pool for a 16-week summer season is about $725.
