GOT A GREEN POOL?:
My method is basically to bomb the pool out with chemicals. "Shock and Awe" as George Bush would put it. It doesn't matter really if the pool has a high pH or a high Conditioner (CYA) level. You are not dealing with a pool at this time but a swamp, so why are you trying to balance a swamp? What matters is killing the algae, and fast. This method is easy and highly effective.
After the algae is killed you can then adjust your chemistry levels.
Some videos show partial draining to lower the CYA levels. Even half the pool or more. This doesn't make sense. If your going to drain half the water out you might as well drain all of it and do a chlorine and acid wash. Also, almost all cities will fine you if you do drain your green pool down into the street. Again, I make it blue first and adjust after.
So is it safe to swim after you destroy all the algae? Yes. Algae technically is not a health hazard -ever swim in a lake? It is the bacteria found in water that isn't circulating or filtering that is the health risk. Once you get the filter cleaned and the water circulating and blue again you can jump in.
Green Pool Clean Up Step by Step:
Make sure the pool can be cleared up vs draining it and refilling the pool. A rule of thumb is that if there is more than 4 inches of sediment on the bottom, a draining may be better. This would be a lot of algae and dirt on the pool bottom so more like a pool that has been sitting unattended for over a year or more. Generally a pool that has only been green for a few months can be cleared up with just chemicals and algaecide.
Step One: Scoop out all of the leaves and debris from the bottom and surface. Don't worry about stirring everything up, you will vacuum at the end of the treatment.
Step Two: Brush the pool as best as you can. Some of the algae might be really tough to brush off. If you have a plaster or Pebble Tec Pool a Steel Algae Brush will help. But a lot of the algae will be loosened once you add the chemicals to the pool.
Step Three: If you have a D.E. Or Cartridge filter take it apart and clean it. The filter type is usually on the label on the filter.
If you have a Sand filter you will just be Backwashing it during this process. For a D.E. Or Cartridge filter you probably will have to clean it again at least one more time or more.
Step Four: Bomb the pool out. You want to bring the chlorine level up to 30-50 ppm to start to kill the algae. A lot of the chlorine will be destroyed by the algae and other organic material in the pool in the first 24 hours. A shorthand guide:
14,000 gallon pool: 4-6 gallons of 12.5% liquid chlorine or a combination of that and 1 lbs. Bags of shock.
20,000 gallon pool: 8-10 gallons of 12.5% chlorine.
30,000 gallon pool: 12-16 gallons of liquid chlorine.
Again, you want to bring the chlorine level up to Blazing High levels.
I suggest using Sodium Bromide to help kill the algae. Sodium Bromide is very effective, however it does “use up” some of the chlorine so don't over do it. I suggest one capful added with one gallon of liquid chlorine. So if you are adding 8 gallons of liquid chlorine, 4 capfuls of Sodium Bromide should be sufficient. You want some of the chlorine to be active so you don't want to add 8 capfuls of Sodium Bromide to the pool. Each Capful is about 4 oz.
Step Five: Run the pool for 24-48 hours straight during the process. You may have to add more chlorine after 24 hours and clean the filter again. No need to vacuum the pool yet. Let everything slowly settle to the bottom first. This may take a couple of days.
Step 6: After the pool has cleared enough for you to see the bottom, you can manually vacuum out the pool. The stuff on the bottom will be dead algae and other organics like dead mosquito larvae and other bugs and plants. If you have a sand filter or a D.E. Filter with a “Waste Mode” vacuum the pool with the Multi-Port Valve to that setting. If you do not have a backwash valve with a “Waste Mode” you can vacuum directly to the filter. Note that you will need to clean the filter after vacuuming if you do not vacuum to Waste.
A portable clean-up pump comes in handy here but it is an investment of about $200. If you plan on using it again it would be a good investment, otherwise just vacuum to the filter and clean the filter. You can see my videos on how to make a portable clean up pump here:
Portable Clean-Up Pump to Vacuum out a Pool: https://youtu.be/bU8No8Jfjrw
Green Pool Clean Up Playlist:
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