How To Clean A Green Pool

How to Clean a Green Pool

When the pool goes green, what should you do? Can green pool water be fixed? The most common cause of green pools is lack of chlorine and then comes along the algae, a very fast-growing plant that can take over pools quite quickly. Algae doubles it’s weight every hour, especially in hotter weather, which is why it can happen practically overnight during swimming season and with warm weather. What causes this rapid algae growth in pools is often lack of chlorine in the water, unbalanced pool water, failing equipment or too many leaves and debris coming into the pool.

10 Steps to Fix a Green Pool

The surest way of ensuring that the pool never turns green in the first place, is not letting your chlorine levels drop below about 2ppm, not for even a day. Therefore, it is important to check these levels regularly, especially after rain or a day of swimming in the pool. We recommended weekly if maintaining yourself.


But if you find yourself in need of a quick Green Pool Recovery you can obviously reach out to a pool professional likes Jim’s Pool Care or you can follow these 10 steps to try and get your pool back to blue. These steps are only a guide and we always recommend with Green Swimming Pools to seek professional help.

How to Fix a Green Pool

  • Always try to evaluate why the pool went green to start with. Was it equipment failure or lack of maintenance?
  • The next steps depend on how bad the pool is. You may be able to filter the pool or you may have to floc the pool.
  • Remove as much debris from the pool as you can.
  • Chlorine shock the water by giving it a healthy dose of chlorine and balancing back the pH as per product instructions.
  • Check the pump and filtration system for any problems or errors, fix if found.
  • Brush the pool walls and floor to unstick all the algae from them, causing it to disperse into the pool water. Again, remove any debris from the pool and clear out the baskets.
  • Backwash the filter. If it is a cartridge filter, remove if you are flocking pool.
  • For media filters, return valve to filter and turn the pump back on and run 24 hours if trying to filter out green pool. Back wash filter and re-assess.
  • If heavily green, you may need to floc and vacuum to waste once the algae drops.
  • Finally, once clear, ensure you rebalance the pool ready for swimming.

My Swimming Pool is Dark Green

If the pool is very dark green where you cannot see the bottom of it, you are likely to need a flocculant for dropping the algae particles to the bottom of the pool. Most green pools can be chemically recovered but in some cases a pool drain and acid wash may be required, but ensure you seek professional advice before doing this. This is important.

If chemically treating, you can also add an algaecide to help by eliminating the process of algae spores growing, however you must have caution when using them as some may contain high levels of copper and may not be suited for your particular pool type or based on your pool water balance. High copper levels can cause staining and can “plate out” on the pool surface in some cases.

Recovering a nasty Green Pool is not for the faint hearted. Often it is best to call in a pool professional who can advise and help. After putting in the time, the effort and paying for all the chemicals used in trying to take care of it yourself, and not getting the result you were after, may cost you more in the long run. You may also have some equipment or other problems that can be assessed by a pool professional.


Jim’s Pool Care would of course love to help you if we are in your area and if we have availability. So, if you are ever unsure or need a hand with how to clean a green pool, just give us a call or book online today: 131 546