As the cooler weather approaches and the pool will be used less frequently, this is a good time for many pool owners to remove stains and beautify their pools. There are several ways that this can be done, but we are going to discuss a No Drain Acid Wash for a plaster or exposed aggregate pool. The benefits of a No Drain Acid Wash outweigh the risk of the traditional drain and power wash type of acid wash.
As I have mentioned there are a couple of benefits to doing a No Drain Acid Wash. The biggest advantage to the homeowner is eliminating the additional cost of paying to refill your pool, you will only need to re-balance your current pool water when completed, as opposed to, draining and refilling the pool. Another benefit to not draining your pool, if your pool is empty – depending on the area of the country you’re in, you run the risk of your pool popping out of the ground. If your pool were to pop out of the ground, it no longer is a pool, it becomes a very expensive dismantling project.
Let’s discuss the procedures to perform a No Drain Acid Wash:
Determine what type of stain you have or what you are trying to accomplish. If you have a stain, is it a metal stain, if so what kind and where did it come from? We have an entire blogpost on how to prevent stains using this simple fix This is important because you don’t want to complete the work only to have the problem reappear. Are you trying to bring back the color on your plaster, remove plaster dust or scale? Remember to have realistic expectations. If your pool plaster is 15 years old, with some yellowing, a No Drain Acid Wash may make it worse, because your plaster is at the end of its life expectancy.
Determine the amount of water in your pool. This is important so that you can apply properly dose the chemicals needed.
Test the water chemistry. The chlorine reading should be below 1 ppm.
Time to add the chemicals. We will start with No Dran Acid Wash. One bottle treats 5,000 gallons. If the product is not available, then you can use Pool Stain Treat in its place. Pool Stain Treat is the same formula with a different application. You will need 1 bottle of Pool Stain Treat/No Dran Acid Wash per 5,000 gal of water and 3 gallons of Pro-Strength Muriatic acid per 5,000 gal of water. Muriatic Acid is available in 2 strengths. Be sure to use the 31.45% product. Mix the Pool Stain Treat/No Drain Acid Wash in a bucket of water, 1 bottle at a time. Pour mixture evenly across the entire pool by walking around the perimeter. Once the Pool Stain Treat/No Drain Acid Wash is in the pool, add the (pro-strength) Muriatic Acid or No Mor Muriatic Acid. For example, you would need 4 bottles of Pool Stain Treat/No Drain Acid Wash and 12 gallons of Muriatic Acid for a 20,000 gallon pool.
NOTE: If you have an attached spa, add 1 bottle of Pool Stain Treat/No Drain Acid Wash with 1 gal of Muriatic Acid to the attached spa, in addition to the chemicals added to pool.
Once the chemicals are added to the pool, immediately brush the pool completely, using a standard combination pool brush. Once the pool is completely brushed, turn the pool equipment off.
NOTE: Although it is unlikely that algae will grow in this environment, you can use a chlorine floater with a tab per 10,000 gal of pool water if necessary.
At the end of the 5th or 7th day, the desired outcome will have been achieved, and it is time to readjust your water chemistry.
Test your water chemistry. Please don’t use a test strip in this process, it is important to use a proper test kit. If you do not have a complete test kit, by all means take the pool water to the nearest pool store and have the run a complete test, your pH and Total Alkalinity will be extremely low.
Because you are doing a completing a No Drain Acid Wash, it is important to raise your pH first, this step will go against standard pool industry thinking, and allow the Total Alkalinity to raise as a secondary process. You will raise your pH using either Soda Ash or pH Increaser. If 10lbs of pH Increaser or Soda Ash is needed to raise your pH 7.4-7.6 ppm, you will need to dilute about 1 lb of product in a bucket of water before adding to the pool and repeat the process. It is time to turn on the pool equipment. We do not want to add the whole amount at one time, as this could cause issues.
Once the pH is back in range, you can begin to raise the chlorine level, doing the same process. Dilute the granular shock in water before casting it into the pool. If using liquid chlorine, walk the chlorine around the deep end. Remember, add the chlorine slowly and not all at once.
Once the No Drain Acid Wash is complete, it is a best practice to use Pool Stain Treat as a maintenance product, 1 bottle of Pool Stain Treat per 20,000 gal every 2 months, to keep the stains away.