Swimming Pool Special
Procedures
Special procedures
Besides the regular maintenance of the pool
and spa there are certain other special procedures that might be
helpful in increasing the life and utility of any swimming
facilities.
Draining the pool or spa is simple, if you
take into consideration certain factors. It might seem obvious that
you use your submersible pump to do the job, but this simple task
can create many problems for it may require certain procedures. For
more information on correct drainage and disposal of pool water,
contact the state or the regional office of the environmental
protection agency.
- Before starting the job, turn off all
circulation equipment at the circuit breakers, so there is no
chance it will start up from a time clock.
- At a commercial pool, run yellow caution
tape around the pool deck to keep unwary visitors from falling
into an empty pool.
- Drain the pool. But make sure to know if
the area is known to have a high water table. Damage to the pool
can be caused by hydrostatic pressure or water tables, thus it
is not advisable to drain the pool during these times.
When draining a pool with your submersible
pump and hoses, direct the flow to a deck drain. Initially watch the
flow into the drain, once you start the pumping, a clogged drain
can flood the backyard or flush the water back into the pool.
Usually the deck drains are made of PVC and may not be able to carry
so much water under pressure. So check for soil erosion under these
drains before draining. If deck drains cannot accommodate the flow,
connect it with the sewer, making sure that it does not back up the
storm drain and flood the street.
In some jurisdictions there might be
restrictions on pumping out pools relative to the permissible volume
and even the permissible chemical makeup. Extremely low-pH water
might have to be neutralized before pumping it into municipal storm
water or sewer lines. Check your local codes before draining.
When lowering a submersible pump into a pool
check for loose wires. Any loose connections or wires might
electrify the water. A ground fault interrupter (GFCI) should be
plugged into the wall socket before plugging in the cord of the
pump.
The new plaster break-in is one of the most
important examples of your professionalism and knowledge of pool and
spa maintenance. By following the procedures outlined in next
sections, without taking shortcuts, you will find new plaster
break-in is an important part.
Why
Break in Plaster?
There are two basic reasons to break in
plaster rather than just turn on the pump and start swimming. The
reasons are:
- Remove the plaster dust from the water.
- To balance the water chemistry so that
water itself does not destroy a good plaster job.
Plaster
Break-in Procedure
The break-in procedure is the same for a new
pool or a replastering of an older pool.
To accomplish this simple task, keep a
step-by-step list of break-in procedures, detailing the brand names
of chemicals used and the daily break-in schedule.
It is important to document that you followed
the break-in procedure that was agreed upon. Keep a clipboard in the
equipment area to list each action taken each day as the break-in
proceeds. The notes should include the date, time, weather
conditions, test readings, and chemicals applied or actions taken.
This is important because plaster discoloration or roughness often
are the result of a faulty break-in and it is much easier to blame
that process than to investigate the plaster job or other hidden
mistakes.
Break-in
step by step
After any new construction of a pool, there
are two basic reasons to break- in plaster. First, to remove the
plaster dust from the water, which will otherwise settle and build
up as hard, rough scale. The pool is filled with water before the
plaster dries, so the actual drying (curing) takes place underwater.
Adding the water before the plaster dries allows it to be pushed
into place against the pool shell, pressed evenly by the weight of
the water. It doesn't shrink, become brittle, or crack. The second
reason to break in the plaster is to balance the water chemistry so
that the water itself does not destroy a good plaster job.
Therefore, the break-in process is designed to create
plaster-friendly water that is neither etching nor scaling. There
are many variations to the steps needed for a successful break-in of
new plaster, but here are a few recommendations.
- Inspect the plaster work for trowel marks
or footprints, and look for signs of sloppy work. They should be
seamless and smooth, without trowel marks or high spots. Bring
any imperfections in the plaster job to the attention of the
builder or plasterer for correction before filling.
- Test the source of the fill water for heavy
metals such as copper, iron, and manganese. If you detect high
levels of metals in the source water, you should be advised that
additional chelating agents will be required and you can adjust
your chemical balancing in general to avoid precipitating these
metals onto the new plaster. Similarly, if the testing of the
source water reveals it to be of exceptionally high or low pH
and/or total alkalinity, adjust it.
- Filling the pool or spa should be done with
care. The water cascading several feet down will damage the soft
plaster below. Provide a cushion for the water when filling in
the pool, so that the weight of the water does not leave any
mark on the fresh plaster. Never walk on the fresh plaster; this
will leave footprints. When filling the pool do not leave it
half way, for this will affect the curing factor of the pool.
For the same reason do not add chemicals into the pool when
filling the pool. Additions of chemicals should be done once the
pool is full.
- When the pool or spa is full checking all
the equipment. Turn on the circulation equipment, filters and
also check the pressure on the filter, for later references.
- Purge all air from the system, especially
from the filter. Filtration at this point is critical. Remove
any air from the filter and run it for at least 12 hours daily
to remove the debris from the plaster-in.
- Do not allow the pool to be heated, or turn
on the fountains or waterfall for at least three weeks after
start-up, for the force of the water can damage the fresh
plaster.
- Test the water for pH, total alkalinity,
and calcium hardness at this point, there should be no chlorine
residual to test. Plaster is made from calcium compounds, and if
the water is low in calcium hardness specifically and total
alkalinity in general, it will leach calcium out of the plaster,
effectively dissolving it. The first component to balance is
total alkalinity. Since this will also raise the pH. Next bring
the calcium level up (unless it is already in the 200- to
400-ppm range) by adding calcium chloride to the water, as
directed to use. Finally, adjust the pH. Generally you will need
to lower the pH, but this must be done gradually. As noted in
the water chemistry, pH readings take awhile to stabilize,
particularly during the break-in process when no conditioner has
yet been added to the water. Test the pH every four hours and,
using the acid demand test, determine the amount of acid needed.
Regardless of the result of that test, however, add no more than
1 pint of acid per 10,000 gallons of water at any one time. In
this way you will avoid spiking the pH. Also, do not add
sanitizer or stabilizer at this point. Algae doesn't prosper on
smooth surfaces, in alkaline conditions like water curing new
plaster, or on surfaces that are constantly being brushed.
- Brush every inch of the plaster surface
thoroughly and vigorously at least three times each day, once
the circulation begins. Brushing knocks loose the plaster dust,
avoiding scale build-up. Brush from the top of the walls down
and from the shallow to the deep end, with the suction
concentrated at the main drain to pull the dust and minerals
into the filter.
- Plaster dust will quickly clog the filter,
so be prepared to clean it as soon as the first day after
starting the circulation. Break down and clean the filter each
time filtration slows and/or the filter pressure exceeds 10 psi
over its clean operating pressure.
- After 2 days, vacuum the pool at least once
each day before brushing using a brush vacuum to aid in the
brushing action and also avoid the wheel mark on the soft
plaster.
- After 4 days, sanitizer can be added,
gradually raising the residual to normal levels. As in all
chemical applications, add gradually and make sure it is
distributed evenly.
Continue these procedures for at least one
week, preferably two till you see no plaster dust coming off when
you brush. Keep swimmers out of the pool during the break-in period.
Any pool or a spa can develop leaks from one
of the many places like, equipment, plumbing or even the pool or the
spa vessel itself.
When there is an unexplained loss of water,
there is some leakage problem. Signs of water in the equipment area
and exposed plumbing will usually yield results that there is
leakage in the plumbing, however, buried plumbing have leaks where
it can't be seen. While the worst leaks require excavation and other
repair techniques, let us find the leaks and deal with them.
Finding
Leaks
As noted previously, the first place to look
for leaks is in the exposed equipment and plumbing, but there are
often visible signs of leaks that are otherwise hidden from view.
Cracks in the pool or spa interior might be a sign of leaks. Tiles
falling off the walls or loose coping stones often suggest
structural leaks from shifting ground, which might have been caused
by a water leak eroding the soil. Even cracked or lifting segments
of deck might indicate the source of a pool leak. Tree roots might
also cause leak.
Evaporation test
Check for the rate of evaporation of water
from the pool or a spa as compared to normal evaporation of water on
any given day. If there is a significant rate of water loss, than
the rate of evaporation, it is sure sign of leak in the pool or spa.
Dye testing
Another simplest method of detecting a leak in
the vessel itself is a dye test. As the name implies, a colored dye
is disbursed in suspected areas and, as the dye disappears, the leak
is found. The dye test can easily be conducted using an old test kit
reagent bottle or similar squeeze bottle filled with food dye. You
will need to check many locations like the cracks near the steps,
corners and the tile fittings. Continue to visually inspect the
interior surfaces, looking for cracks or discolored patches of
plaster. After you have thoroughly examined the pool with the dye
test, you will know what repair problems you are faced with.
Drain-down test
This method is that it is an indicator, not a
precise tool. If you have tried the evaporation test and dye
testing, or if you are not a good diver and wish to skip the dye
test, try the drain-down method. The objective is to determine when
the level stops lowering as a result of the leak. Marking the level
of water evaporation at the same time each day to establish a rate
of leak.
Leak detectors and pressure testing
When the previous methods fail to help you
locate the leak, there are two other methods of leak location. There
are electronic listening devices called geophones that can actually
hear water dripping or flowing. By applying such devices around the
pool and related plumbing, an operator can identify where water is
moving out of the system. These devices are expensive and their
operation requires a great deal of experience and skill.
The second method used to find leaks is
pressure testing equipment. It is not difficult to pressure test a
plumbing system but the amount of time and additional equipment
(plugs, adapter fittings, compressed air, and related fittings)
makes this type of testing impractical. Many pool builders and
plumbing contractors are equipped to pressure test pool or spa
systems. Certain companies conduct pressure testing.
Skimmer
Repair and Replacement
Skimmers are essentially separate devices
hanging on the side of the pool or spa wall, and due to shifting of
the earth and constant erosion from swiftly moving water make small
leaks in this spot inevitable. When the plumbing is of copper leaks
in this location are accelerated by the practice of adding chemicals
directly to the skimmer. The high acidity of the chemicals eats away
at the copper in these fittings.
Plastic skimmers, when used, are prone to
separation at the seams. To determine if that is the cause of a
leak, use the drain-down method in just the skimmer. Turn off the
equipment and plug the skimmer suction ports. If the water level
drops at a rate faster than evaporation, the skimmer is leaking. PVC
plastic skimmers can often be repaired in place, without excavating
the skimmer.
Repair or replacement of a skimmer require
some simple excavation, masonry, and basic plumbing work. Before
starting, drain the pool level below the skimmer level and turn off
the circulation equipment. To prevent the debris entering the pool
and the plumbing line, plug the throat and the suction port with
rags. Now cutting the area around the skimmer, remove the concrete,
making sure not to damage the plumbing. Once the plumbing and the
skimmer are exposed, remove the old skimmer carefully. Pressure test
the plumbing for any leaks. Now clean the area around and set the
new skimmer in place and plumb it to the existing suction lines.
Fill in the area with the removed soil and then with concrete to
give extra stability to the skimmer. Trowel smooth and finish the
area. If the new skimmer doesn't exactly correspond to the opening
in the pool wall, adapt-cut the pool wall opening and set in the
skimmer. If the new skimmer is not the same depth as the old one,
use depth-extender collars to bring the level up to the correct
height, and then set it in the skimmers.
On older pools that include an equalizer line
through the pool wall at the base of the skimmer, patch the wall and
install a two-port skimmer instead, plumbing one port to the suction
line and the other to the main drain, or permanently closing it off
if there is no pipe to the main drain from the skimmer location.
The replacement of the skimmer in fiberglass
or vinyl-lined pools, will be more a process of unbolting and
disassembly, replacing the skimmer and gaskets that separate it from
the pool wall. Since each assembly is different, reassembling should
be done by carefully noting the steps while disassembling.
Patching
and Repairing
Plaster
It is the best opportunity to check for any
delaminations, plaster blisters or the pop-offs, when the pool is
drained for any reason. And depending on the damage done the work
may require patching to plastering job.
The causes of delamination, also called
calcium bleed, can be numerous. From sub quality construction to
improper water chemistry and to rusted rebar. So check the entire
area of the pool for any plaster faults.
Once you have identified blisters, chip the
loose plaster away all around the area until you reach solid, dry
plaster. When completely exposed, clean the area of all water and
loose debris. To make sure the final patch blends in and appears
even, clean up the jagged edges of the blister area by sanding the
perimeter. You are now ready to patch.
If the delamination is due to rusted steel or
rebar, expose all the rusted steel and cut it out. Fill the area
with the quick-set cement, allow it to dry and then give it a finish
with the surface plaster patch. If the area is large, try to replace
the same amount, size, and distribution pattern that you have
removed and then proceed to repair as above.
The other application method is underwater,
where you work by hand with a fist-size ball of material and push it
into the patch area with your fingers. Again, use more than you need
so you can scrape off the excess, feathering the edges into the
existing plaster for a smooth finish. It saves time, money, and
water over draining the pool. In case of deeper works, it is
advisable to drain the pool.
One last plaster patching technique is used to
fill small surface cracks. The objective of patching small cracks is
to slightly widen the crack so that it will accept patch material.
Using a small chisel create a slight V shape along the crack. Fill
the exposed area, either troweling on the patch material or rubbing
it into the crack with your fingers and smoothing over the resulting
repair with a straightedge.
Coping and tile
Popped tiles and coping stones, may be one of
the reasons of water leakage and erosion. Loose tiles are sometimes
an early sign of built up pressure. And since the coping stones are
set on concrete deck, excavating the underlying deck and checking
for the problem needs to be done.
To remove the tile or deal with the coping
stones it is advisable to drain the water level up to the tile
level. Remove the tile or the stone from its bad section carefully
so as not to damage other tiles. Chip the tile away to expose the
mortar bed of pool wall beneath. Cleanse the area and fill in any
loose soil area and then reassemble the tile back into the wall by
using the plaster patch material as the backfill.
To remove the coping stones, it is easier to
pull them free if they are loose already. If the stones are not
loose then you may need to cut the joints using a concrete saw,
before pulling them free. Chisel and clean the underlying area as
needed. Remove old expansion joint material and examine the area
between the pool deck and the bond beam. If there is no space
between the coping and tiles, for shifting and expansion, both the
stone and the tile will come loose. This is the cause of the
problem, and it will cause more loose stones and tiles in the future
unless the pressure is relieved and an expansion space provided.
Chisel or cut away any material that is pressing against the pool
wall, never cutting the pool wall or bond beam to create the
expansion joint.
When the expansion joint is complete, fill in
any dirt that might have eroded away to complete the backfill area.
Prepare the plaster patch material. You can also use a premixed
waterproof product like Thoroseal, applying two thin coats before
resetting the stones. The advantage of using a waterproof mortar is
that you prevent water from weeping or leeching into the backfill
again.
Clean the stones of dirt and old, loose
mortar. Apply a light coat of patch material to the underside of the
stone, then sufficient patch material to the mortar bed to bring the
stone up to its original level. Tap the stones in place with a
rubber mallet. Prepare a brown coat of mortar to reset the tiles.
Apply the tiles in the same manner as the coping stones. Regrout the
stones and tiles. Grout can be premixed material purchased at the
supply store or hardware store, or it can be mixed by combining one
part white cement with two parts sand. Overfill, then wipe away the
excess to a smooth, level surface. Do the same with the tiles.
Complete the expansion joint. Fill the joint
with sand almost up to the last inch. Fill the last inch with
flexible mastic or silicone joint sealer, which can be poured as a
liquid or injected like caulk. Follow the product label directions
for application, especially concerning temperature and humidity
ranges.
If you understand the basic underlying
construction of the coping and tile area of the pool or spa, you
will be able to make these basic masonry repairs. Many will not be
as complicated as described, requiring only rehanging a few tiles or
resetting a single loose stone. if that single tile or stone keeps
coming loose however, or if more than one are loose, follow the
procedures described earlier to determine the cause and effect a
long-term repair.
Vinyl liners
There are numerous manufacturers of vinyl
liners for pools, using several different compositions of vinyl,
PVC, or rubber-based materials. Thus the liners are sold with
detailed instructions and repair kits.
Locating leaks in a vinyl liner is the same as
in any other vessel. Start with an evaporation test to verify that
there is a leak, then use the dye test or drain-down method to
locate the exact leak location. Since vinyl-lined pools are often
assembled aboveground, it might be a simple matter of checking
around the pool and under any adjacent decking with a flashlight
looking for wet areas.
Most repair kits detail the process of drying
and cleaning the area to be patched with a solvent, roughing up the
area to be glued with sandpaper for a better bond, then gluing a
patch of the same material over the tear or puncture.
Acrylic spas
Cracks in molded fiberglass or acrylic spas
can be easily patched. To detect the leak, follow the previously
described methods using evaporation, dye, or drain-down. Leaks in
spas often occur where plumbing meets the spa shell. Shells often
move away from their deck supports when the ground shifts and are
especially susceptible to soil erosion problems. Since bather loads
and displaced water are high in relation to the total size of a spa,
water frequently washes away fill or base materials allowing the
weight of bathers to shift the spa and separate plumbing.
Cracks or breaks in the acrylic can be
repaired with materials available at the supply house. The technique
is similar to patching small cracks in plaster, where you widen the
crack to accommodate a fill material. Follow the package
instructions for mixing, curing, and drying times. Slightly overfill
the crack, then wipe off the excess for slight shrinking takes place
during drying. When it is completely dry, sand off the excess down
to the level of the surrounding surface. The patch must be painted
to match the color of the spa. Color powders or liquids are provided
in the kit to mix with the base enamel paint, also provided. A clear
topcoat seals the paint job and adds luster to the finish. The
topcoat is also provided in the repair kit.
Most builders today offer shallower, smaller
pools that provide adequate room for swimming laps and recreation in
a small backyard, but require less attention and upkeep. Builders
today will actually build a new, smaller pool inside the shell of a
large older pool, using the original plumbing and equipment, and
filling in the difference with backfill and landscaping.
There are several other ways to remodel a pool
or spa. New decks and landscaping will improve the look of an older
pool. As for the vessel itself, the water technician can offer
resurfacing of the interior, new tile, and recaulking of the
expansion joints to help the look of an existing pool or spa.
Plastering
and Replastering
Plasters significantly impacts the chemistry
of the pool, so it is important to understand the plastering process
to know how chemicals will affect the plaster surfaces and vice
versa. Because there are several approaches to replastering a pool
or spa, it is important to understand and evaluate the needs of the
pool. Plastering a new pool or replastering an old one should be
done by the professionals but since nothing is more critical to the
successful maintenance of a pool or spa, it is valuable to
understand the plastering process.
New Plaster
Let us understand the new plastering process:
The gunite or concrete pool shell must be
clean of loose dirt, algae, and water before plaster is applied. To
accomplish a contaminant-free environment, wash and scrub the shell
with chlorine and water to remove organic waste. Next, wash and
scrub with an acid solution of one part muriatic acid to four parts
water to eliminate minerals and concrete dust.
Plaster will not adhere to an acidic surface.
Every bit of acid must be removed from the concrete shell.
Neutralize the acid with trisodium phosphate (TSP) or baking soda.
Use 1 pound in 5 gallons of water of either product, creating a
wash. Thoroughly scrub and pump out the shell. The concrete of the
shell must be moist but not have standing water. The shell is now
ready for plastering.
Remove all plumbing outlet nozzles and any
removable hardware such as light fixtures or ladders. Stuff rags in
the plumbing to keep plaster out of it and tape off the threads of
any fittings. Finally, tape the bottom of the tile line to keep it
clean.
The plaster material is a mixture of one part
white cement for every two parts aggregate (sand and marble dust,
also called marcite, or sand and limestone). Calcium chloride is
added to help the mixture set up more quickly, but never more than 2
percent of the weight of the cement (not the total mix). Plaster is
mixed in a cement mixing drum using a paddle mixer. Color powders
are added to the mix if the final plaster is to be colored. Water is
added, roughly 2 gallons for every 100 pounds of dry mix, until a
heavy semi liquid consistency is achieved. Water should be gradually
added for the right consistency, for excess of water will not give a
good plastering material.
The plaster is applied by trowel. The first
coat should be scratched on thin to fill and smooth out the
roughness of the concrete. Then, two more thicker coats are applied
while the underlying coats are still wet. It takes several
plasterers to apply the material fast enough to finish in a few
hours so that the pool can be filled before the plaster dries out
and cracks. Care must be taken to avoid leaving plaster on the tile
or fittings. When cleaning these, avoid running water over the fresh
plaster; this can leave furrows or stains. Break in the new plaster
as described previously.
When plaster cures, the topcoat becomes almost
transparent, allowing any imperfections in the shell to show
through. The first coat of scratch plaster is important in leveling
out such imperfections, although it cannot completely hide them. If
gray lines or slightly darker spots appear at various places after
the pool is full, this is usually the reason. Therefore, the finish
job of the shell is as important as the scratch coat.
When the concrete shell is poured by hand,
such imperfections are common. In these cases, it is valuable to
grind or chisel down any high spots prior to plastering. A good
plaster job over a well-made gunite shell will last up to 20 years.
Replastering
When plastering the shell for the first time,
the plaster permeates the pores and roughness of the gunite surface,
creating a firm mechanical bond. When replastering, the new plaster
must adhere to the old smooth surface with either a new mechanical
bond, a chemical bond, or a combination of both. There are several
ways to prepare the old surface to enhance the bonding of the new
plaster. Depending on the condition of the old plaster, one or more
of these preparations might be used. The surface preparation is the
most important step of the replastering process.
The first preparation method is to etch the
old surface with acid, leaving it rough and pitted and thereby
promoting a better mechanical bond for the new plaster. The old
plaster is washed with raw muriatic acid to deeply etch the surface.
Scrubbing and washing after application of the acid, helps in
removing the loose dirt and organic waste. All the acid must be
thoroughly washed.
The other method to remove the old plaster, is
to chip it away, creating a jagged, rough surface for the new
plaster ton enhance the mechanical bonding of the new material.
Finally, the removal of the old plaster can be accomplished,
although expensively, by jack hammering the old material off of the
pool shell. Care should be taken not to crack the pool shell.
After preparing the surface with any of the
methods, a chemical bonding agent is added to the scratch coat. The
bonding agent helps the scratch coat adhere to the shell on one
side, then helps the plaster adhere to the scratch coat on the other
side.
Other than these preparation differences, the
original plaster job and the replaster job are alike. A good
replastering job can last more than 10 years.
Fiberglass
Coatings
The technology for surfacing gunite pools with
fiberglass is new. Because fiberglass coatings and their
applications are a unique technology and requires specialization in
such works. Fiberglass coatings require the same surface preparation
as replastering. The best mechanical bond is achieved by roughing up
the surface prior to application. Fiberglass sheeting is laid on the
pool interior and painted in place with chemical resins and
fixatives. There is insufficient data available to evaluate if such
coatings exceed the performance of plaster, but the obvious benefit
of a fiberglass coating is that water and maintenance chemicals
cannot corrode and destroy it like plaster.
Paint
The purpose of coatings of any kind over the
gunite material of the shell is to prevent leaking, because concrete
itself is porous. Modern pool paints are an attractive, inexpensive
way to coat gunite, fiberglass, plaster, or any other interior
surface with a smooth, colorful, waterproof coating. It is an
inexpensive alternative to other coatings.
Before painting, evaluate the surface being
covered. As with other coatings, the success of painting depends
largely on the preparation and qualities of the subsurface being
covered.
Though paint is an inexpensive alternate, it
will not last much longer than three to five years and might begin
to peel or dissolve prior to that. Colors might be vivid initially,
but will fade throughout the life of the paint, especially the
brighter the original color.
As a general rule, cover old paint with new
paint of the same type. You can use water-based epoxies to cover
chlorinated rubber, but not the other way around. Always follow the
paint manufacturer's label directions and guidelines.
A general understanding of the procedure is as
follows.
- Prepare the surface by cleaning, and
removing any loose materials from the pool.
- Acid wash the entire area to be painted, to
etch the surface to create a roughness that will help the paint
adhere.
- Rinse and scrub again with clean water and remove any acid or
dirt adhering.
- Allow the surface to dry thoroughly.
Following the product directions, mix the paint, enough to do
the entire first coat.
- Apply a thin but even coat. The first coat
will use two to three times as much paint as subsequent coats,
except when applying over fiberglass.
- After waiting the manufacturer's
recommended time between coats, apply a second and, if
necessary, a third coat. On all coats, but especially these
finish coats, paint the entire surface at one time.
- Let the paint cure as recommended by the
manufacturer, then refill the pool or spa.
Expansion
Joints
The expansion joints are the places where
water may fill in and corrode the joints or sometimes the joints
shrink and crack.
Repairing expansion joints is time-consuming,
but an easy job. First remove the sealant from the joint with the help
of an appropriate tool. Clean the joint of any loose dirt and
sealant residue. There are several types of mastics and silicone
caulk sealants that can be used to close expansion joints. Simply
follow the directions on the package, making sure of that the
sealant has been applied properly.
Acid
Washing
To remove scale causing minerals and
chemicals, it is necessary to drain the pool from time to time an
this is a good time to acid wash the pool.
Before acid washing, it is important to know
how old the plaster is and if it has been acid washed before. If the
plaster is nearing the end of its useful life (10 to 15 years),
there might not be enough material to wash without stripping the
surface down to the gunite. Similarly, if the pool has been acid
washed two or three times already, it might be time to consider
replastering, painting, or some other recoating.
The traditional method of acid washing requires draining
the pool as
described.
Standard drain method of acid washing
After draining the pool, the pool should be prepared for acid wash.
Remove any loose or removable hardware
such as ladders, rails, or metallic return outlet nozzles. Remove
the main drain cover. Clean out the main drain. If
the pool is plumbed with copper, stuff the outlet pipes, skimmer,
and main drain with rubber plugs or rags soaked in water and soda
ash to neutralize and/or keep out as much acid as possible. Rinse
(and scrub if needed) any other organic material (oils, leaves, and
dirt) from the plaster, because the acid will not dissolve these and
therefore will not clean the plaster beneath.
Also make sure to protect yourself with rubber
boots, gloves and a respirator to protect you from inhaling acid
fumes. Always take care of your person while doing the acid wash by
keeping a garden hose with running water handy.
The effectiveness of acid washing is a function of the
strength of the mixture and the length of time it contacts the
plaster. During the contact time of the acid with the area (30
seconds), scrub the area with a stiff- bristle brush and then wash
it off with clean water. If the stains do not disappear, you might
need to leave the mixture in contact longer. Sometimes it may need
higher strength acid solution to remove the stains. Keep rinse water
flowing on the pool bottom when you are not actually rinsing an area
that has been acid washed to neutralize acid on the pool bottom.
Keep the pump operating to remove the waste from the hopper. The
running water from the hose keeps the bottom and the hopper from the
drastic effect of the acid from the long hours of work, since all
the acid that collects at the bottom and gets drained from the
hopper will be diluted as it leaves the pool.
After cleaning the tile lines and removing
the stains, rinse the pool area thoroughly with water. Clean all the
fixtures and hard wares before reinstallation. Let pool dry
completely before painting.
Fill the pool as per the procedures described
in the draining section. Let the water circulate in the pool for
some time, and then check for the chemicals and water chemistry,
making the adjustments as needed.
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