By Frederick M. Hueston PhD
Over the years I have been called in to evaluate numerous stone and tile failures on pools, spas, fountains and other water features. Failures such as tiles coming loose, grout missing, discoloration and build up of mineral deposits, etc. In most cases all of these failures can be contributed to improper maintenance such as using the wrong chemicals to clean to unbalanced water chemistry.
The following is a simple guide of what to do and what not to do when it comes to cleaning your pool or water feature.
Getting rid of the crud
One of the most common problems with swimming pools and water features is a buildup of mineral deposits. These deposits often appear as a white film deposited on the surface of the tile. These deposits can often develop into heavy crusts. Most of the time the only way to clean these deposits off is to break out the Muriatic acid and go out with a scrub brush. The problem with most acids is that will attack the grout as well as the tile. I have seen cases where there was so much acid used in a pool that all the grout turned to powder and was washed away. If there is any marble in the fountain the acid will etch and dull the marble. Most of these failures are the result of mis-use of muriatic acid. So what is the proper way to clean these deposits off the fountain? The following is the proper procedure for cleaning mineral deposits off tile:
Step 1. Preparation. Before using any acid make sure to wear the proper protective equipment. For muriatic acid this would chemical resistant gloves, respiratory mask and goggles.
Step 2. Protect all adjacent surfaces that might be affected by the splash.
Step 3. Mix one part muriatic acid to two parts water. Make sure to pour the acid into the water. DO NOT pour the acid in first and than the water. This could cause the acid to splash up.
Step 4. Apply the acid solution with a sponge or rag. Do not use spray or pour it on. Agitate with a nylon scrub brush until all the deposits are removed.
Step 5. Rinse the tile with a solution of water with once cup of odor less ammonia added to the one gallon of water. One cup of baking soda to one gallon of water will also work. This step is important
since it will neutralize the acid.
Step 6. Rinse entire surface down with clean water.
The above procedure should reduce the amount of damage done. There are alternative non-acid cleaning methods using bead blasting but this is not a do it yourself technique and will require a professional contractor.
Proper Water Chemistry
Another major problem with pools and water features is improperly balanced water chemistry. The most common mistakes made are as follows:
1. Not monitoring water chemistry frequently. You should be checking the ph, total hardness,
bromine and chlorine at least twice per week. By monitoring these levels more often only minor adjustments will be necessary.
2. Do not allow the pH to get above 8.0. When the pH increases. The activity of chlorine is
dependent on the pH levels. For example, when the pH is 8.5 the chlorine is only about 10 %
active but at 7.5 the chlorine is about 50-60% active. Keep this pH in check will prevent you from over-chlorinating the water and will also save you money on chlorine.
3. Total Dissolved Hardness (TDS) and Calcium hardness are also important for water balance and can affect the precipitation of mineral deposits. These should be checked at least once per month. If the TDS is above 1500 ppm the water will need to be drained and replaced. This cannot be corrected with chemicals. This is a major cause of mineral deposits and staining on tile and stone in pools and water features.
4. Alkalinity should be 80 to 140 ppm. Lower or higher alkalinity will affect the effectiveness of
chlorine or bromine levels. This should be monitored monthly as well.
5. If you have a salt water pool the cells should be cleaned often. Corroded or calcified cells will reduce the amount of chlorine generated.
6. If your pool’s filter system is a sand or DE filter, try to avoid backwashing too often. Most systems will only require backwashing when the gauge rises from 8-10 psi from clean.
7. Clean the filter baskets often. If these are clogged this reduces the amount of water flow and can cause not only poor circulation but build up of deposits, scum algae, etc.
8. If you use liquid chlorine add it in the evening, not during the day.
9. Brush the walls and tile both above and below the surface with a soft nylon brush. This will keep the deposits, algae and scum from adhering.
10. Check for damaged tile and pipes. You should be checking the pool on monthly basis for
cracked tile and grout, broken pipes, etc. These should be repaired immediately.
A properly maintained pool or water feature can go years without a major overhaul or restoration. Of course you must start with the proper water balance and a sound water tight system.
If you run into problems or issues that are causing failures make sure to consult an expert to prevent further deterioration.