Green Pool Clean Up Methods 101

What is the best method for clearing up a green pool? Shock it, Floc it or drain it? Let me touch on each of these for you here.

Draining a green pool sounds easy and logical but there are a great many hoops you will need to jump through to even do this successfully without getting a ticket from your county or city. Here in my area of California, it is illegal to drain a green pool into the street. You must first turn it milky blue and even then draining into the street is illegal and you must drain it into the main sewer line. After draining it the walls might still have dead algae on them and the empty basin will be an ugly swamplike slimy mess that you will have to clean up. You may have to do a chlorine wash as well before you refill the pool. So draining is not a simple process. 

FLOC Method:

Using a pool Floc has its benefits and you might want to purchase a bottle or dry container of Aluminum Sulphate (Floc) to help accelerate your pools recovery. Basically, the Floc will help to clump up all of the dead algae and organic particles and sink them to the pool bottom. Generally, you will leave your pool off for 24-48 hours for the Floc to be more effective. Once everything drops down to the bottom the pool will be much clearer, and everything will be easier to vacuum out. 

In most cases, you need to have a filter with a multiport valve so you can vacuum to “Waste.” Or you can use a portable clean-up pump if you have one.  Floc is optional but can help to clear the pool up faster, especially if you have an inefficient filter type like a Sand Filter. You will need to vacuum to “waste” since the bottom will be covered with dead algae dust and also 8-14 lbs of the Aluminum Sulphate (Flocculant). A regular cartridge or DE filter cannot take that much dust so you can’t vacuum a pool directly into the filter. 

It's a long method since you have to leave the pool off for 2 days. But it is easy. Add the floc, and put the multiport in “recirculate” for 30 minutes. Turn the pool off for 48 hours. Vacuum to waste. 

Shock and Awe Method:

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: 14 gallons of 12.5% liquid chlorine or a combination of that and 1 lb. Bags of shock. 

20,000-gallon pool: 20 gallons of 12.5% chlorine.

30,000-gallon pool: 30 gallons of liquid chlorine. 

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 overdo 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 worthwhile investment, otherwise, just vacuum to the filter and clean the filter.

It may take a week or two weeks to completely clear up but the pool will eventually turn back into a crystal clear blue pool. 

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