Rain can mess with the chemical composition in your pool. It can alter your pH and alkalinity, which can be detrimental to your chlorine levels. If your pH and alkalinity levels are off, it will eat your chlorine. Leaving your pool without chlorine will cause black algae spots to show up in the bottom of your pool. You can get rid of these algae spots, but it will take some time and effort. See below for some tips on how to get rid of black algae at the bottom or your pool.
Check Your Water
Test your water with a simple test kit that you can find at your local pool store. The water test kit will help you test your alkalinity, chlorine, pH and stabilizer levels. Some have strips that you just dip into the water and you have your reading after just a few seconds. You can also take your water to your local pool store to have it tested. Once your water is tested, you can see what you need to add to your pool. Most likely if you have black algae, you need more chlorine. Add the chemicals that are needed to get your levels back up to where they need to be.
Once you have the chemicals at the proper levels, you can add an algaecide to help get rid of the black algae spots. Since black algae is very difficult to get rid of, you may need to do a little bit of scrubbing. Add as much algaecide as needed depending on the size of your pool. Read the instructions on the back of the package to see how much to use. Add your algaecide and then use a stiff pool brush to scrub the affected areas.
Adjust Water Jets
Adjust the water jet in your pool to help circulate the water around your pool better. If your water isn't moving, it's more susceptible to getting black spots. Your water jet should be moving the water around your pool in a circular motion. The more water that is moving, the better. Most jets have a directional return that you can adjust easily.
Other Cleaning Tips
- Keep plenty of chlorine in your pool at all times. Use a floating chlorinator in your pool. You simply add chlorine tablets and allow them to dissolve in the water.
- Vacuum your pool often. You can use an automatic pool cleaner or vacuum it yourself. It should be done every two to three days to keep dirt out of the pool.
- Change the pool sand. For pool filters that use sand filtration systems, be sure to change the sand yearly. Dirty sand inhibits the filter's ability to clean properly.
- Swim. Swimming in your pool helps to circulate the water, so grab some friends and have a pool party. Once in awhile, get into the pool in a pair of socks to scrub the bottom and sides of the pool.
Keep your pool chemicals at the proper levels and be sure to clean your pool often to help keep black algae from forming. If you have any other problems with your pool or can't get the spots to come off, contact your local pool contractor for help.