|
You return from vacation and the pool has turned green, slimy
and cloudy. The day after a big, all day party the pool has gone
cloudy with that nasty hint of green. Every pool owner knows when
algae gets going in the pool. Every pool owner also knows that only
an algaecide will kill the pest and let the pool return to pristine
condition. So after a quick trip to the pool store or garage you
add algaecide and hope for the best. But wait, what IS an
algaecide? What are you putting in the water with such high
hopes?
Algaecides are chemicals that kill algae as opposed to
sanitizers like chlorine that prevent algae and bacteria from getting a foothold
in the first place. Algaecides are the last line of defense to
prevent draining a pool and starting over. Although the brand names
and claims are numerous there are really only two kinds of algaecide available
today; metallic and quaternary ammonias. Though both types can be
very effective they have different characteristics. Choosing the
right algaecide is key to getting the problem solved and swimming again.
Metallic Algaecides Great for winter
closing and algae blooms.
The very earliest types of pool algaecide were copper
based. Copper is a proven killer and is extremely effective.
Copper, either as copper sulfate or elemental copper is suspended in a
carrier liquid (water) by a chemical called triethanolamine and added to pool
water. Copper concentrations vary from 1 to 7 percent depending on
type. Though as effective as any of the newer types of algaecide
copper has drawbacks: it can stain pool hardware and turn hair
green if chlorine concentrations are too high. It also builds up
over time and continued use and can stain even a properly balanced pool.
Silver based algaecide is also available. Used
to suppress algae and bacteria in electricity-generating fuel cells on space
craft, silver algaecide capitalized on use by NASA to win pool customers.
Silver algaecide does work but much more slowly than copper.
Along with the drawbacks associated with copper algaecides, silver based
algae killers are as expensive as, well, silver!
Quaternary Ammonia (Quats) Great for maintenance and
algae blooms.
Quaternary ammonia based disinfectants are everywhere;
hospitals, nursing homes, restaurants, day care centers and……….swimming
pools! Very effective as surface disinfectants at concentrations as
low as 2.5 percent, most pool algaecides use a concentration of 30 percent to as
high as 60 percent. The main drawback to quaternary ammonia
algaecides is foaming. Added to pool water the agitation provided
by the pool pump is enough for the algaecide to add nice suds to a pool.
Not nice to look at but not a real problem. Quats are
relatively inexpensive and a good anytime algaecide if a little foam isn’t a
bother.
Polyquats are a refinement of quat algaecides and
eliminate the foaming problem entirely. Available in concentrations
as high as 60 percent they do the job perfectly but at prices approaching $30
per quart a little foaming might not look so bad. The high price
might also be because there is only one U.S. manufacturer!
Low foaming quats are a compromise.
Significantly less money than polyquats the foam problem is greatly
minimized at a price that makes more sense to many pool owners. Low
foam quats are very effective.
Using algaecides
-Always add algaecide first. Let it work
overnight before shocking. Chlorine will oxidize and destroy the
algaecide if added too soon. If the algaecide is metallic staining
is additional reason to wait.
-Check the ingredients. Look for the active
ingredients; copper, ammonia etc. Also check the active
percentage. If it’s below 30 percent look elsewhere.
In particular avoid gallon jugs of algaecide. Generally this
bargain stuff has only 5-10 percent active ingredients and will actually cost
more to do the same job.
-Spread the algaecide as evenly as possible around the
perimeter of the pool. Better distribution means faster action.
-Don’t overdose. More is NOT better especially
if using a metallic algaecide.
Rob "Dr. Duck" Coxworth is the driving force behind http://www.webfoot leisure.com/, an
on-line retailer of swimming pools, supplies,equipment and accessories. Rob has
spent many years in the pool industry in a variety of roles; CEO, manufacturers
rep, consultant, National Sales Manager and part time pool float. Dr. Duck likes
to write about pool issues and share the information he's gained from working
with pool industry firms over the years. |
tweet this!
