It’s important to note that you should not try to vacuum green pool water until you have removed any and all organic debris using a pool net, and have added the proper chemicals to the water, and done proper brushing so that the green algae has visibly settled to the bottom of your swimming pool.
There are essentially 2 ways to vacuum green algae once it has settled on the bottom of your pool – pool to waste (if you have this option) OR through your filter (requires more work).
1. Vacuum green algae through the Waste Method (Easiest and Safest for Equipment)
The easiest way to eliminate the algae that has settled on the bottom of your pool is to bypass the filter and vacuum from the pool to waste.
Hopefully, you have a multiport system and can vacuum your pool to waste, or your pool installer plumbed in a waste line on your system in front of your cartridge filter.
Set up your waste line and vacuum the pool to waste getting the algae and debris out of the pool. Don’t let the water level get too low during this process, if it gets more than 6 inches below the tile, stop. Turn the system off and refill the pool and repeat until the whole pool is vacuumed.
2. Vacuum green algae through Your Filter (Only if You Have No Other Alternative)
If you have to vacuum through your filter, ideally you will want to use an old cartridge that you can dispose of when you have completed the process.
Begin vacuuming as you normally would, and if you see dirt or dead algae is bypassing your filter and blowing back into the pool, your filter needs attention before you can proceed. Try cleaning the cartridge (you may need to do this several times). If the debris is still bypassing the filter and blowing back into the pool you need a repair to the filter itself – by a service professional.
After you have successfully vacuumed your pool and replenished the water to the right level it’s time to get the system restarted. On a pool with a multiport valve, it’s important to restart the system in stages so you don’t pump dirty algae fill water back into your beautiful pool.
First, backwash and rinse the filter very well. We recommend running it through this cycle at least 3 times, or more if needed. Use your sight glass and look at the discharging water.
If your DE filter has sat for a while you should get a pool professional to do its annual dissemble and clean. The same goes for sand filters that have not been fluffed and rejuvenated within a year or two.
Once the filter is cleaned and DE has been re-added to DE filters, set the system to run for 12 hours. If you have any questions on bleeding the air safely off your system refer to the owner’s manual of your pool filter.
If you have a cartridge filter, now is the time to put that new filter element into the system and throw away the old one. If the water didn’t clear with the old element, repeat the last steps with the new one in place before moving on.
As a final step add your last jug of bleach and a half gallon of acid and allow this to circulate for 24 hours.