A double edged knife, the acid wash can make your pool look spectacular, but at what cost?
After several years of use, a swimming pool’s surface will start to show it’s age. Many times there will be some staining from metals or other contaminates. If only there were a way to clean it up right and make it look new again. Enter the acid wash, a risky, yet rewarding process that involves applying muriatic acid directly to the pool surface. The risks involved are high because muriatic acid is highly corrosive and literally removes a thin layer of the pool surface to expose a fresh layer. If your plaster is not thick enough, the acid could expose the underlying gunite structure. Despite this major drawback, acid washing is quite popular and looked upon as a cheap method to restore a pool’s surface. The results are never guaranteed and most businesses will present the customer with a liability waiver explaining the risk involved.
Although I will describe the process of acid washing a pool here, every pool is different and you should be sure to consult with a pool professional about your particular situation. You should never attempt to acid wash a pool without the proper knowledge, protection, or training.
An acid wash begins by draining the pool. Depending on the location, surroundings, time of year, etc., there may be precautions to follow when doing this. All water must be removed before beginning. This is usually accomplished by using a vacuum to suck up the last few gallons around the deep end.
A plastic watering can (think of the kind for gardening) is used to apply the acid. The muriatic acid is mixed with water at about one part water, one part acid. In extreme circumstances, a stronger mix of acid may be required. Before applying the acid, be absolutely sure there is adequate ventilation, a water supply (garden hose), and you need proper breathing protection. When you are ready to apply the acid, sprinkle the deepest area of the floor and let it fizz for about 15 seconds before rinsing it off with the garden hose. At this point, drop 15 to 20 lbs of sodium bicarbonate into the water to neutralize the rest of the acid as it enters the pool of water. Be sure to mix the sodium bicarbonate into the water so that it does not leave a spot on the floor.
From here I usually wash the short wall of the deep end following the same procedure. Pour the acid on the surface being sure to cover it completely and then rinse it off after 15 seconds. The longer you wait, the more it will work. After the short wall in the deep end, make your way down the other walls toward the shallow end. Do the short wall in the shallow end and the steps, then from the deepest part of the slope, work your way back up to the shallow end washing the floor. If needed, add some more sodium bicarbonate to the water to neutralize the acid. You might expect to use between 8 and 16 gallons of acid and a 50 lb bag of sodium bicarbonate. Once all of the surfaces have been acid washed, the water in the floor must be removed with a sump pump and vacuum.
Hopefully the results are good at this point. There is no way to go back and if there are any problems, the pool may need to be resurfaced. Contact us if you would like our advice on your specific situation.