Jumping into the cool and comfortable swimming pool is certainly a great escape from the stinging summer weather. However, swimming in a dirty pool can hinder the enjoyment and keep people away from the pool. Stains are common in pools and need regular maintenance to keep them clean. Sometimes stains are fairly easy to clean, but sometimes they are stubborn and demand more than scrubbing. Pool stains on the walls or bottom of the pool can result from molten metal in the water, or by organic matter left in the pool. The first clue to check for pool stains is the color.
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Method 1 of 4: Recognizing Stains
Step 1. Look at the color of the stain to classify the cause
There are a variety of common stain colors. Once identified, you can begin to think about ways to further countermeasures and prevention. Depending on the cause, you'll still need a unique cleaning plan.
- The two main categories of pool stains are metal-based and organic. The colors also vary.
- These color combinations include green-brown, red-blue, blue-green-black, green-brown-red, red-pink, or brown-black-purple. Try to distinguish, the stain in your pool is a color combination.
Step 2. Watch out for organic stains at the bottom of the pond
It's most likely caused by leaves, berries, moss, worms, dead animals, or other organic debris that will stain if allowed to float on the pond surface. If not cleaned immediately, these stains will sink and rot at the bottom of the pool. Fortunately, organic stains are easy to clean.
- Organic stains are usually green, brown, or bluish-purple. It may be easy to check for organic stains if you can see organic debris such as leaves settling to the bottom of the pond.
- If you suspect an organic stain, try applying a small amount of chlorine directly to the stain. Organic stains will be easy to clean with a soft brush, while metal stains will remain.
Step 3. Beware of all non-organic or metal based stains
This substance can enter the pool unnoticed, through well water or corrosion of copper pipes. It only takes copper the size of a coin to oxidize in the pool and cause large stains. The types of metals that can sneak into your pool include rust, manganese, iron, and copper. If there are rust-colored stains on the pool wall under the stairs, the source may be metal, and you should check the ladder for corrosion or not. Check near steps, around gutters, and under pool rims for discoloration. Stains that appear reddish-brown or very dark are usually related to metal in the pool water.
- The metals that commonly cause stains in pools are iron, manganese and copper. Copper is sourced from ionizers and corrosion of copper and brass pipes. This will make the stain blue, green, teal, black or dusky purple. Iron comes from well water, corrosion of iron pipes and pipe joints resulting in brown, gray, or grayish-brown rust stains. Manganese comes from well water and causes pink, dark brown or purple stains. Calcium comes from plaster, grout, mortar, or cal-hypo chlorine shock and appears as white crystals.
- If you get a metal-based stain, it's important to know exactly what type it is so that it can be removed.
- A common cause for blue-green copper-colored stains is incorrect chemical treatment. Low pH levels and high chlorine can also erode the copper layer in pool heaters. Proper water balance maintenance will make it easier to keep the pool from developing stains.
Step 4. Seek professional help
If you want to leave stain removal to the experts, use the yellow book to find a pool specialist or pool retailer in your area. You should bring a sample of your pool water so they can test and decide exactly what type and level of metal is staining your pool. Professionals can then recommend additives specifically designed to remove metal stains.
Step 5. Make sure you take the correct water sample to check
Use a clean bottle or cup and hold it upside down so the opening is facing the bottom of the pool. Push it all the way under the water and turn it over again to take a water sample. Do not take water samples near jet engines or skimmer holes. It is better to take an example from the middle of the pond. If this is not possible, take it as close to the center as possible so that the test results are accurate.
Step 6. Make sure you perform the TOTAL metal test as part of your routine inspection
The FREE metal test measures only unattached metal, but the total metal test can measure all metals in the test sample.
Step 7. Use a test strip to test the water at home
Take a sample of water from the center of the pond. After that, quickly dip the test strip sheet which is still dry into it. Without wasting any remaining water, hold for about 15 seconds. The strips will change color, and you'll need to match them to the guides on the back of the bottle. There are many different types of test strips you can buy to check for various things, but the important thing is to check the pH, alkalinity and free chlorine levels.
Use a test strip at least once a week. Take a water sample to your local pool shop once a month for a professional inspection, especially when opening and closing the pool
Step 8. Try the liquid test kit
There are very sophisticated liquid test kits, but for your own pool, you can still use pH and chlorine or phenol red test kits and OTO Chlorine test kits. Liquid test kits can be very accurate, but you need to be able to translate the resulting colors. For example, once you dip the test chemical into the sample water, the color will change, and depending on how light or dark it is, you will need to accurately match the directions on the test kit case, to determine the correct treatment plan. Please be aware that it can be difficult for you to translate the different colors that appear.
- OTO Chlorine is a chemical that tests the total chlorine content. It is a yellow liquid which is added to the sample water. The yellower it is, the more chlorine content in the pool.
- Phenol red is a red chemical that is added to a small amount of sample water to ensure a pH balance. The redder the water, the higher the pH balance.
- With liquid test kits, it is difficult to see the low color spectrum. Make sure you use a white background when checking, to be accurate.
Step 9. Determine if your water source is the problem
If you are filling the pool from a well, test the water directly in the well before filling the pool. If you decide that the metal content is high, drain the pool by about 1/4 or of it, then fill it again with filtered water. Then circulate the water for at least 48 hours, then retest. If the metal concentration is still high, repeat the process from the beginning.
If your water source is good, metal ingress is most likely due to corrosion. Check the pool equipment and make sure nothing is melting metal into the pool water
Method 2 of 4: Organic Stain Treatment
Step 1. Remove organic matter from the pond surface
Usually, greenish-brown stains are associated with algae or leaves that settle to the bottom of the pond. These items should be disposed of as part of pool maintenance. Organic stains aren't usually difficult to remove, but over time, the pool will start to turn a dull light brown in color, and if it's like this, it won't be able to clean. This brown discoloration occurs very slowly and is difficult to notice at first.
- If you have a tree with branches hanging over the pond, watch out for leaves, branches, or fruit that may fall into the water. Use a skimmer to clean regularly.
- Any organic waste floating on the bottom of the pool should be cleaned with a pool vacuum. You can use a hand vacuum or an automatic that uses a sensor.
Step 2. Wash the pool with acid
If permanent stains do appear, dry the pool and wash it with acid, if the pool has plaster liner. This can't be done every time, as it requires you to peel off a thin layer of pool plaster. In order for the bottom of the pond to return to a shiny white, you should wash it with acid once every five years.
Step 3. Try the enzyme shock method and rub vigorously to remove the stain
It can quickly remove greenish-brown stains that have accumulated due to organic waste. You can also try using an enzyme-based chemical. All natural pool enzymes will eat organic matter and make it easier to clean stains without vigorous scrubbing and without the use of harsh chemicals that damage the pool liner. If the stain is around the pool's water line due to material floating on the surface, an enzyme-based cleaner can help remove organic compounds and oils by speeding up chemical reactions. This helps make the stain go away on its own. Continue with the brush thoroughly to make sure all the trash and oil has been removed.
Step 4. Shock the pool with chlorine
Organic stains are best treated with plenty of chlorine, then pour in a little TLC and scrub vigorously. You can use a long-stemmed brush to reach around the pool. Pour a small amount of chlorine over the organic stain, so it's gone right away. Caution, this method is good for plastered pools, but don't do it on vinyl pools because it can damage the liner pattern.
Test the water to ensure the balance of pH and alkalinity levels are up to standard. The pH level should be between 7.4 and 7.6, while the alkalinity should be between 100 and 150 ppm (parts per million)
Step 5. Remove the localized stain with muriatic acid and a vigorous brush
Slowly and carefully pour the acid down a PVC pipe, then apply the acid to the stain on the pool wall. Be warned, if the entire pool is slightly stained, you may end up with a stark white spot with dark edges.
After using a stain remover, make sure you shock the pool so that there is enough chlorine in the water before it turns green with mildew
Step 6. Skip the harsh chemical solution and harsh rubbing
Try using a tile grout scrubbing brush to get to thin crevices. There are two types of brush heads that you can buy. One for the concrete pool, and the other for the vinyl pool. So make sure you check which one you need before buying. After purchase, use it on the pool to clean stains in hard-to-reach locations.
Method 3 of 4: Treating Metal Stains
Step 1. Take the right steps to get rid of metal stains in your pool
One option is to buy a metal cleaning product that you will put in the skimmer bucket for a few days. This is the first step in most stain removal processes and will help with the overall pool cleaning effort. There are many brands to choose from and all offer varying degrees of strength. So, if you can, ask a professional pool attendant, which product is best for your case.
Step 2. Turn off all swimming pool machinery and equipment near the pool water
These include chlorinators, metal ionizers, generators, UV systems, and ozone generators. It is also a good idea to avoid contact with pool heaters, chlorine generators and other non-filtration systems near the pool during stain removal and heavy chemical treatments.
Step 3. Lower the chlorine level in your pool, between 0 and 2 ppm (parts per million)
The lower the chlorine content, the less ascorbic acid is needed to clean the pool. You can wait for the chlorine levels to drop naturally through rain, over time, but if you're pressed for time, you can add sodium thiosulfate to the water, following the directions on the package.
Add algaecide to pool water. Be sure to follow the instructions for use on the box regarding what method of dam application is required for your pool size. This will prevent moss from growing, by suppressing chlorine levels
Step 4. Remove metal stains with ascorbic acid
Minerals react best to chemicals, and if you believe your stain is metal related, or if the suggestions above for removing organic stains don't work for your pool, try ascorbic acid-based pool products. It's a citrus acid that's commonly found in some fruits, and when concentrated, it's incredibly powerful. If you want to try an easy and effective home remedy, crush a few vitamin C tablets and rub them into the stain. After a few minutes, check to see if the stain is starting to fade.
- Remove large stains by adding ascorbic acid to the pool. Sprinkle evenly onto the surface of the water. Start with 1/2 pound of ascorbic acid per 10,000 gallons of water in the pond.
- Set the filter to the “circulate” position, then turn it on. Let the ascorbic acid work for half an hour.
- Check the pool to see if the stain is gone. If it's still there, add more ascorbic acid, then let the filter circulate the cleaning process for another half hour. Repeat this process until the pool is clean.
Step 5. Restore a healthy chemical balance in the pool water
It is important to always monitor the pH, alkalinity and hardness levels of each element in the correct range, depending on the size of the pond. Don't forget to turn on the automatic chlorine, chlorine generator, UV system, ozone generator and metal ionizer. Place a pack of fresh metal remover in the skimmer basket to keep the metal content low, as well as help keep the pool spot-free all season long.
Method 4 of 4: Prevent All Stains
Step 1. Make pool maintenance a routine
Prevention is always easier than cleaning. Bring a sample of your pool water to be tested for the ideal chemical balance by a professional or with a special device at home, every week. If you're filling your pool water from a source other than "city water," you should also test that source water as groundwater is high in iron and stains.
- Perform cleaning with small shocks every week to prevent the development of mildew.
- Scrub the bottom of the pool several times a week as a precaution.
Step 2. Prevent metal stains from recurring
Make sure you test the water regularly for metals, as stains will always recur if your pool has a high metal content. Remember, metals can occur naturally and enter through source water that is fed into the pool, or through corrosion from pool equipment or plumbing systems. So, make sure to always monitor metal levels every week.
- Use isolating agents, also known as chelators. This substance binds minerals in a special solution that prevents minerals from floating freely in the water and causing stains.
- Disposable absorbent bags are also capable of cleaning metal. Put one bag in the skimmer basket so it absorbs a variety of metals such as copper, iron, manganese, cobalt, silver and nickel.
Step 3. Make sure your pool is clean of organic stains by keeping it away from natural debris
Either by wiping the pool or using an automatic pool vacuum to clean leaves, berry litter and fallen branches and twigs. Don't forget to buy a winter-resistant pool cover sheet and use it when the pool is not in use.
Dark stains can appear from mud or fallen leaves that enter the pond. If you can't prevent these things from getting in, try re-coating the pool with dark plaster or liner to cover up these types of stains
Tips
- Test the pH and alkalinity of the pool every week, as well as the TDS level of the water every month or every four months.
- Pool-specific chemicals, chemical solutions, and test kits can be purchased at home improvement stores and pool specialty stores.
- If you're using a stain remover from a pool specialty store, you'll need to lower the chlorine level to below 1PPM to keep it from competing with stain remover products.
- Plaster pool owners must pay attention to the pH, alkalinity and TDS levels so that the liner is not damaged.
- After cleaning metal stains with ascorbic acid, the pool should also be treated with a metal insulating agent to maintain the correct chemical balance.
- Ascorbic acid is able to clean stains. Try a Vitamin C chewable tablet. Put a few drops in a sock, mash it finely, then rub it directly onto the stain. It takes quite a bit, it's true, but it's effective at removing most blemishes in no time.
Things You Need
- Sodium thiosulfate
- Algaesida
- Vitamin C Tablets
- Ascorbic acid
- Commercial rust prevention enzymes
