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Algae (cont.)
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.....algaestatic
(that is, to prevent algae growth).
Chitin has the ability to coagulate and
remove a wide variety of suspended
materials and impurities from the water.
This allows the sanitizer to more
effectively kill contaminants
unobstructed. It also improves the
effectiveness of the filtration
equipment. Sold under the trade name
Sea-Klear, chitin can be a valuable
weapon in your algae arsenal.
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Algaecides
and Algaestats:
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Quaternary
Ammonium Compounds:
A low grade type of algaecide, Quats, as they are called, will usually
have "10" somewhere on the bottle, representing 10% active ingredient. Although
available at a lower cost, quats tend to produce a small amount of surface foaming. They
are most effective as an algaestat, that is, as a prevention, not a cure.
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Polymers:
Polymers are long, complicated chemical chains that behave in water both as an algaestat
and an algaecide. They are available in percentage strength of 30 - 60%, are non foaming,
and work well as general, all around algae treatments. Poly-Quats are a blended compound
of polymer and quats.
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Copper
Based:
Copper is a proven algaecide and algaestat. Available in varying non foaming strength of
3 - 10%. It works very well on all types of algae, but it has the drawback of staining white
plaster surfaces a light blue/green color if it precipitates out of solution. Most copper
based algaecides are chelated, which means that agents have been added to prevent this,
such as Lo-Chlor Algaecide.
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Silver
Based:
Silver has been shown to be an effective bacteriostat, which means that it works to
prevent bacteria from reproducing. Non foaming and effective with pink algae. In high
doses, reactions with sunlight can cause colloidal silver to deposit as black stains on
white plaster. When using copper or silver algaecides, the use of a sequestering agent is
recommended.
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Chlorine
Enhancers:
These are not algaecides, but work to provide a
synergistic boost to hypochlorites when added separately, but at the same time. Sold under
trade names like Mustard Buster, Yellow-Out or Yellow Treat, it is most effective on, you
guessed it, yellow algae. Since it is not an algaecide, the makers are not required to
tell what it is made of, but we do know that it works quite well, in conjunction with a
little brushing and vacuuming on your part.
Too late to prevent it...How do I
kill algae?
First off,
balance your water, paying
particular attention to pH. Secondly,
check your filter system and clean if
necessary. Adjust valving for optimum
circulation and allow it to run 24 hours
a day until the pool clears. Turn on
automatic cleaners to help stir things
up. Backwash as necessary.
For suspended green algae,
shock the pool...hard. Put in as
much hypochlorite as it takes to turn
the pool a cloudy, bluish/gray color.
Brush the walls and floors towards the
main drain. Backwash the filter when the
pressure gauge indicates the need (8 -
10 lbs. above clean reading, after
backwashing.) Using a flocculent may be
a good choice if the pool is extremely
"swampy". If you cannot see the bottom
of the pool, and it is filled with
leaves and debris, it may be wise to
drain the pool,
acid wash and refill it.
After the chlorine level has come down
below 5 ppm, add an
algaecide and
brush the pool again. When it all
settles,
vacuum the pool (to waste, if
possible). Check and
re-balance the pool water if
necessary.
For algae which is not suspended, but
only clinging to the walls, follow the
same advice above, first shock with
brushing, then add an algaecide, brush
again, vacuum to waste (preferred) or
vacuum and then backwash the filter. Use
of a
steel bristled brush is recommended
for algae on plaster pools (use
nylon brush on vinyl). Filter,
Filter, Filter!
For black algae, the brushing part is
very important. You must tear through
the protective layers so the chemicals
can destroy the plant from the inside
out.
Pumice stones work well to knock off
the heads of black algae. (Don't forget
to vacuum them up later, and backwash
them out of the filter ASAP). Also
effective on the black algae nodules is
sprinkling granular trichlor over the
spots (of course if they're on the wall
this is next to impossible). Rubbing the
spots on the walls with a
trichlor tablet or stick can also be
effective to knock off the heads and get
trichlor directly to the roots. Follow
up with a dose of
copper algaecide, or high strength
polymers. Simazine, an herbicide,
was a very effective black algae
treatment, but is no longer available in
America.
If algae has been an ongoing problem in
your pool for several years, you may do
well to drain the pool. Many years
of algae builds up dead algae cells and
lots of other solids in the water that
contribute to its rejuvenation.
Acid washing and/or pressure washing
is preferable once drained, to kill the
roots of the algae embedded in the
plaster. NEXT: Change the sand if you
have a sand filter or change the
cartridge if it is a cartridge type.
Sand should be changed every 5 - 7 yrs
(or every 2 if you use Baquacil), and
cartridge filters should have new
elements every 1 - 2 years. If you have
a D.E. filter (good for you!), you
should remove the elements, spray clean,
soak in a 10 : 1 water/ bleach solution,
rinse and replace. A well functioning
filter will prevent algae.
Another item to look at is the method of
sanitation and the type of filtering you
have. Far too many pools out there were
sold with marginal filter systems, meant
to run 24 hrs per day. Well, these
systems get old and tired, or the new
owners only run it 12 hrs per day (or
less). For good algae prevention, we
need a combination of good filtration,
sanitation and circulation. It may be
time to consider changing the old
pump and
filter. It's cheaper and easier to
pay a little up front for more
chemicals, electricity or better
equipment than all the money and
aggravation spent on fighting algae
blooms.
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