NPTpool Pool Finishes, Tile Maintenance FAQ

Calcium deposits usually originate from grout or setting mortar. To remove, scrape it off the tile. Another method for removing calcium deposits is the pumice stone. Pumice is a light porous glassy lava stone that can be rubbed over a pool stain to remove it. You can get a pumice stone that can attach to your telescopic pole or a pumice stone that has a handle you can swim with.

Do not use any type of acid that you would use on clay house bricks. Always try scrubbing with a firm brush and dish soap first. If the stain persists, brick paver supply companies carry a cleaning solution that is safe to use on pavers. If all else fails, remember that one advantage gained by using pavers is that you have the option of simply replacing the few stained culprits.

Leaves and dirt may stain concrete. Pressure washing can remove these soils and restore original brightness to concrete and coping stones. A light acid washing on the coping stones also works very well, and algae or mildew can be lifted by scrubbing with a paste of bleaching agent. If you do not have any cleaning agent on hand, you can try powdering the area with Baking Soda and then spraying it with vinegar before you scrub it with a brush.

Pavers are generally maintenance free. Cleaning with a high pressure cleaner is a common way to keep pavers clean. Over time, re-sanding might be necessary.

Patterned concrete pavements are merely slabs of concrete that are embossed with a pattern. Therefore, they are prone to the same problems with freeze/thaw cycles, namely cracking and spalling. Pavers won't crack or spall. Stamped concrete requires expansion joints every 10 feet or so, which are very distracting in some patterns. Also, unlike pavers, patterned concrete pavements don't allow access to underground utilities or the ability to make repairs. At virtually the same price per square foot installed, pavers are clearly a superior choice.

The great thing about pavers is that they are easy to repair. They can be pried out and replaced with new ones at any time. This makes pavers a very cost efficient product, for there are no real high costs involved in repairing.

Cover frequently traveled areas of the pool deck with no-slip mats to prevent wear and tear. Keep metal furniture off of the pool deck. Rust stains from metal chairs can stain your pool deck. Clean your pool deck frequently with a leaf blower or hose. Clean up spills as soon as they drop to prevent staining. Keep your deck area clear of overhanging trees. Leaves and fruit that drop on the deck can stain it. Likewise, avoid spilling fertilizer on your pool deck. Fertilizer contains iron, which can leave a hard-to-remove orange stain.

"Scale is the precipitate that forms on surfaces in contact with water when the calcium hardness, pH, or total alkalinity levels are too high. Results from chemically unbalanced pool and spa water. Scale may appear as grey, white, or dark streaks on the plaster, fiberglass or vinyl. It may also appear as a hard crust around the tile."IPSSA Basic Training Manual 2006, pg 188, Glossary

"DO NOT turn on pool heather until there is no plaster dust in the pool."National Plasterers Council, NPC Start Up Card, September 2012 edition
Turning the pool heater on prematurely can damage the heat exchanger. Plaster dust is usually gone in approximately 5-10 days.

"NO SALT SHOULD BE ADDED FOR 28 DAYS"National Plasterers Council, NPC Start Up Card, September 2012 edition

Per NPC Start Up Card, on day 7 brush vac pool if any remaining plaster dust is visible. No non-wheeled cleaners can be used before 14 days.

"Wheeled devices should not be used in the pool until after 28 days."National Plasterers Council, NPC Start Up Card, Sept 2012 edition
Putting a wheel cleaner in the pool prematurely can cause wheel marks/ tracks to show up on the pool finish.

It is recommended that you do not swim in the pool until the water is properly balanced and sanitized.National Plasterers Council, NPC Start Up Card, September 2012 edition

"At no time should any person or pets be allowed in the pool during the fill."National Plasterers Council, NPC Start Up Card, Sept 2012 edition
The pool finish is still somewhat impressionable during the filling phase and walking around in the pool can leave foot prints that will become permanent as the finish hardens. Foot prints tend to show up at night under the illumination of the pool light which tends to cast a oblique angle of light on the finish exacerbating any surface irregularities.

"Brush the entire pool surface thoroughly at least twice a daily to remove all plaster dust."National Plasterers Council, NPC Start Up Card, September 2012 edition
Brushing your pool twice a day for the first 14 days after pool has been plastered is one of the most proactive steps that you can take to protect your new investment and maximize the aesthetic quality of the pool finish. There after brush the pool at least once a week.

"The chemical reaction between hydraulic cement and water forming new compounds most of which have strength-producing properties."

"Hydraulic cements set and harden by reacting with water. During this reaction, called hydration, cement combines with water to form a stone-like mass."National Plasterers Council Technical Bulletin Number 2, January 2010

"The term curing is used in reference to the maintenance of a favorable environment for the continuation of these chemical reactions; that is, the retention of moisture within or supplying moisture to the concrete and protection against extremes of temperature. It is through early curing that the internal structure of the plaster is built up to provide strength and water tightness."

"Curing is typically done by immersing the cementitious coating in water as soon as possible after final set. The hydration of the cementitious compounds will continue underwater."

"By immersion or "ponding" curing of a swimming pool’s cementitious surface, the hydration process is allowed to proceed without the accelerated loss of moisture from evaporation, wind, and other factors. This "ponding" curing will also greatly reduce the tendency of the surface to develop shrinkage cracking."National Plasterers Council Technical Bulletin Number 2, January 2010

If the water is shut off during the filling of the pool after new pool finish application it is highly likely that there will be a visible difference in the finish at the point where the water stopped filling. This is commonly referred to as "ring around the bowl" and is caused by the fact that the dry pool finish material will hydrate at a different rate then the submerged finish. Simply put the section of the pool that stayed submerged will look darker than the section that was allowed to dry out. It may take over one year for the finish appearance to even out if this situation arises, and may require remedial action to rectify.

"Based on temperature and type of finish, fill the pool to the middle of the skimmer or specified water level without interruption as rapidly as possible with clean potable water to help prevent a bowl ring."National Plasterers Council, NPC Start Up Card, September 2012 edition

Thoroughly test the water, balance it and remove all metals.

Testing the fill water is an important step in the preservation of your new pool finish

"Recently, many parts of the United States have undergone significant changes in the potable water delivered from local municipalities to the homes and businesses in their water district. Some of the changes have been brought about by drought conditions or extreme flooding and the need to find alternative water sources. Population growth in certain areas has also created the need for alternative sources of water, which can alter the chemical makeup from previously existing levels. Whatever the reason, the need to test fill water should no longer be an option, and it is strongly recommended that all plasterers, builders, service companies, and start-up persons make pre-testing the source water a mandatory requirement in their business practices. This will help minimize the likelihood of surface issues whether a new pool, remodeled pool, or simply a pool that is being drained due to the high mineral composition or cyanuric acid levels of older pool water.

There are a variety of problems that may arise from three fill water factors. These factors are: 1) tap or fill water that is potentially aggressive due to low pH, low calcium hardness, or low carbonate / total alkalinity, 2) tap or fill water that has high pH, high calcium hardness, or high total alkalinity contents, or 3) some fill waters may have elevated levels of dissolved metals in them. The most common are copper and iron, and sometimes manganese. Low levels of calcium hardness, total alkalinity, and low pH can lead to etching of surfaces, dissolution of grouts, and damage to the pool equipment. These problems can be visible in the pool as surface discoloration issues, colored water, and deteriorated metals in pumps, heaters, valves, and other metal components.

High calcium levels, high total alkalinity, and high pH may lead to such problems as scaled pool surfaces, staining discoloration, cloudy water, and equipment issues such as plugged filters and heaters, along with poor circulation.

Dissolved metals in the tap water can lead to colored pool water and staining discoloration of surfaces and grouts."National Plasterers Council Technical Bulletin Number 1, January 2010

"Water that has a very low calcium and magnesium content (water hardness) – usually means less than 100 p.p.m. or 6 grains. Also, water that has gone through a water softener. Pools and spa should never be filled with soft water from a softener. Water with less than 100 p.p.m. of hardness should be increased to a minimum of 150 to 200 p.p.m. using calcium chloride."IPPSA Basic Training Manual, 2006 pg 189, Glossary
Pool water is constantly trying to find equilibrium. If the pool water is out of balance it will try to balance itself by pulling out what it is missing from the pool finish or tile grout and deposit what it has too much of on pool finish surface or tile. Filling the pool with water with very low calcium hardness water will cause the water to try and extract the calcium from the pool finish and this is can damage the pool finish or tile very quickly.

"As with all chlorine products different chlorine compounds may create different issues. The daily use of stabilized chlorine can cause a steady rise in the Cyanuric Acid levels in the pool. Be careful not to over stabilize the pool water. The maximum cyanuric acid level allowed in commercial or public swimming pools by most every health department in the U.S. is 100 p.p.m. There are a few states that allow up to 150 p.p.m."

The IPPSA recommendation for Residential Pools and Spas: Minimum 10 p.p.m. Ideal: 30-50 p.p.m. Maximum: 100 p.p.m." IPSSA Basic Training Manual 2006, pg 45

Yes, some salts have anti caking agents that can stain a new pool finish.

More importantly salt can have a negative impact on the total dissolved solids of the pool, (affects LSI and the balance of water chemistry). Because of this the minimum recommended time to wait is 28 days and some people wait as long as 45 days to add salt.

"A means of expressing the degree of saturation of water as related to calcium carbonate (CaC03) solubility. A calculated number used to predict whether or not a water will precipitate, be in equilibrium with, or dissolve calcium carbonate."IPPSA Basic Training Manual, 2006 pg. 180 Glossary

"A term used to indicate the level of acidity or alkalinity of pool water. Too low pH causes etched plaster, metal corrosion and eye irritation. Too high pH causes scale formation, poor chlorine efficiency and eye irritation. Proper range for pH in swimming pools is 7.4 to 7.6"IPSSA Basic Training Manual, 2006 pg. 185 Glossary

"The total amount of alkaline materials present in the water. Also called buffering capacity of the water. It is the water’s resistance to change in pH. Low total alkalinity causes metal corrosion, plaster etching and eye irritation. High total alkalinity causes scale formation, poor chlorine efficiency and eye irritation."

Parameters for Total Alkalinity: Minimum 60 ppm Ideal 80-120pm Maximum 140 ppm Simply put "Total Alkalinity determines the speed and ease of the pH change."IPSSA Basic Training Manual, 2006 pgs. 35, 40, 41

"Alkalinity due to the presence of carbonate ions (C03-2)"

Also known as corrective alkalinity. Only corrected alkalinity is used to calculate the LSI.IPSSA Basic Training Manual pg 47-48

"The amount of free chlorine in the pool or spa water that is available to sanitize or disinfect the water. Sometimes called residual or available chlorine."

"Also Total Available Chlorine. The total amount of chlorine in the water. It includes both free available and combine chlorine."IPSSA Basic Training Manual, 2006 pg. 191

"Undesirable, foul-smelling, body irritating compounds formed when insufficient levels of free available chlorine react with ammonia and other nitogren-containing compounds (swimmer and bather waste, fertilizer, perspiration, urine, etc.). Combined chlorine is still a disinfectant but it is a much weaker, ineffective form of chlorine."IPSSA Basic Training Manual, 2006 pg 172 Glossary
Combined chlorine is treated by adding more chlorine until the "break point" is reached.
"Breakpoint chlorination is the process of adding sufficient free available chlorine to completely oxidize all organic matter and ammonia or nitrogen compounds."IPPSA Basic Training Manual, 2006, pg 168 Glossary
"Shock treatment is the practice of adding significant amounts of an oxidizing chemical (usually non-chlorine oxidizers such as sodium persulfate or potassium peroxymonosulfate) to the water to destroy ammonia and nitrogen compounds or swimmer waste."IPPSA Basic Training Manual, 2006 pg 188 Glossary

Pool finishes are typically made utilizing white Portland cement. White Portland cement is a hydraulic cement which means that it sets and hardens once water is added to it. Pool Finishes are also referred to as "ponding or immersion cured" products, meaning that they are designed to be cured under water. Allowing any pool finish to set dry any longer than necessary is highly unadvisable. A pool finish can be compromised in as quickly as 24 hours given the local environment on a given day.

Delamination, bond failure, craze cracking and structural cracking are all common events that occur when pools are left dry too long.

Any time that a new pool finish has been applied or the pool has been emptied it is necessary to add the proper chemicals to bring the water into balance. The parameters for properly balancing water is available from organizations like the Pool & Hot Tub Alliance (PHTA) and the NPC.

New pool finishes can have a dramatic impact on the quality of the water due to the hydration process of the cement. While the cement continues to hydrate and harden it releases calcium hydroxide which transforms into calcium carbonate with elevates the pH and alkalinity levels in the water. If left untreated these elevated levels can have serious detrimental effects on the new finish that can be un-reversible.

A proper Start Up procedure protects and preserves the new pool finish and facilitates a longer service life with greater aesthetic appeal.

"The pool finish will start to hydrate immediately after mixing, with the majority of hydration taking place within the first 28 days. This critical time period is when a finish is most susceptible to staining, scaling and discoloration. Proper start-up procedures including timely brushing and constant monitoring and adjusting of the pool water is mandatory. The following recommended start-up method is based on procedures shown to produce the best aesthetic results. Due to unique local water conditions and environmental factors, parts of these recommended start-up procedures may need to be modified to protect the pool finish. For example: filling the pool with extremely low calcium hardness, low pH or low total alkalinity levels may necessitate changes to these procedures. Brushing and monitored chemical2 adjustments will be mandatory by the homeowner or a trained pool technician during the service life of any pool surface."National Plasterers Council, NPC Start Up Card, September 2012 edition

"Cementitious surface coatings are actually semi-permeable membranes. They allow small amounts of moisture to permeate through and into the substrate, over time. However, many plaster applications that are properly placed and satisfactorily finished are improperly diagnosed or deemed wrongfully to be faulty by people who believe the coating is supposed to be "waterproof" and not watertight. In fact, cementitious surface coatings are not intended to completely stop moisture penetration."National Plasterers Council Technical Manual, Section 1.1 Watertightness
Pool finishes are not waterproof. When needed pools are waterproofed before the pool finish is applied.