Why am I getting black mold in my pool?

More likely algae growth. Black mold would not grow under water. It needs moisture and something organic to feed on.

It is important to test the PH level of your pol every 3-4 days, especially in hot weather and use the appropriate chlorine mixture to keep the pool in balance. The links William provided includes great info that I won't repeat.

It's probably algae. Have you tested the ph of the water?

Black mold would be highly unlikely. Check with your pool product supplier for a testing kit that will help you correct the issues that cause algae growth, which is most likely what the issue is.

Humidity is the cause. You need more ventillation or a dehumidifier!

With the extream heat we have been having a lot of my neighbors are getting the same thing. It is not mold it is algae. My neighbors have been using Clorex Pool and Spa treatments.

This is more than likely algae since it is underwater. You might want to get the pool water tested and treat, your local pool supply stores can do this and have the recommended supplies to fix the problem.

Like all algae, black algae flourish in water, where they can photosynthesize and easily multiply. Growth is particularly common in pools with pH imbalances, low chlorine levels, and poor water circulation and filtration.

Shock your pool and then brush it away with your pool brush.

The spores of black algae can travel to your swimming pool on other objects. Wash pool toys and accessories in bleach and put your family's swimsuits through the washing machine to avoid reintroducing black algae to your pool. Shock your pool.

Thanks for the help everyone

I'm not an expert, but I can offer some suggestions that might help with the black spots in your pool. While I can't say for sure if it's black mold, it's crucial to address any concerns promptly to maintain a clean and safe swimming environment.First, it's a good idea to visually inspect the affected areas and see if the spots can be easily brushed or scrubbed away. Sometimes, these spots could be caused by organic debris or other factors that aren't mold-related.If the spots persist and you suspect mold, it might be wise to consult professionals who specialize in mold remediation. They have the expertise to assess the situation accurately and can provide guidance on how to eliminate the mold safely.

Hi Bracha: I'd have someone look at it who is experienced. If it's black mold, you don't want to fool with it because when anyone is in the water, the mold spores can get into their eyes, nose, ears and mouth and cause serious damage.

You’re probably dealing with black algae rather than mold. It can be stubborn, especially in areas with poor circulation. Try scrubbing the spots, shocking the pool, and running the filter longer than usual. Keeping your chlorine level steady afterward should help prevent it from returning.

Warm Damp Conditions and not enough Ventilation

Hi Bracha, hope this helps you.

Maintain proper water chemistry and sanitation

1. Balance chemicals: Regularly test and balance your pool water. Aim for a pH between 7.47.4 7.4
2. and 7.67.6
3. 7.6
4. , total alkalinity between 8080
5. 80
6. and 120 120
7. 120
8. ppm, and a free chlorine level of 2−42 minus 4
9. 2−4
10. ppm.
11. Sanitize consistently: Keep your free chlorine at a consistent level to prevent algae growth. You may need a higher level for more chlorine-resistant algae.
12. Shock the pool: Shock your pool with a high dose of chlorine weekly or after heavy use to oxidize contaminants and eliminate algae spores.
13. Use algaecide and phosphate remover: Add a weekly maintenance dose of algaecide to prevent algae growth. Use a phosphate remover to eliminate food sources for algae, especially if you have high levels from fertilizer runoff or other sources.

Ensure proper circulation and filtration

1. Run the pump and filter: Keep the pump and filter running long enough for the water to circulate at least once a day, especially in hot weather.
2. Clean the filter: Regularly clean your pool filter by backwashing or rinsing it to ensure it is working efficiently.
3. Create circulation: Adjust jets to eliminate dead spots and use an automatic pool cleaner to help keep water moving throughout the entire pool.

Manually clean the pool

1. Brush surfaces: Frequently brush the walls and floor of your pool, paying special attention to corners, steps, and ladders where algae can hide.
2. Skim and vacuum: Skim the surface daily to remove leaves, bugs, and other organic debris before they can break down and feed algae. Vacuum the pool to remove any debris that has settled at the bottom.
3. Use a pool cover: Cover your pool when it's not in use to block sunlight and prevent debris from falling in.

You are getting black mold in your concrete pool because of a combination of factors like poor water chemistry (high pH or low chlorine), worn pool surfaces that hold moisture, and poor circulation. Concrete is porous, making it an ideal surface for algae to take root and difficult to remove compared to other pool types like fiberglass.

So I was reading this post on AquaDoc about why pools get black mold and man, it kind of makes sense, kinda scary too. If you don’t keep water chemistry balanced and your filtration is lazy, mold and algae can sneak in. People think a pool’s just water and maybe some chlorine but it’s way more. If there’s leftover debris, leaves, or even tiny dirt bits, and you don’t clean or filter well enough, that becomes a cozy home for spores.