So you need to get rid of Pool Algae Fast

You need to get rid of algae in a pool fast, maybe you are under pressure and need to get it done in a hurry. Maybe you take care of your own pool and have a party coming this weekend. Maybe you’re a professional service company, and your customer is in panic. Either way, you need to get a pool cleaned in the shortest possible time.  

In this article, we’re going to show you how to get rid of algae in a pool quickly and break down the steps you’ll need to cover in the next 48 hours.

So let’s not waste any more time!

Day 1 Fast Algae Clean Up

The first day is where the majority of the work will be done in getting rid of the pool algae. The more thorough a job you do the first day, the more quickly you’ll get rid of your algae.

Prepping the Pool

This first part is going to take a little elbow grease; anywhere between 15-45 minutes depending on the pool. The most time consuming will be skimming, brushing and vacuuming.

Check and Clean Filter

Make sure you’re starting with your filter system at optimum. Check the pressure and see if it needs a cleaning before getting started. Depending on what kind of shape your pool is in, you may need to clean it a couple times before the pool is clean.


First things first; you need to get as much junk out of the water as possible using a skimmer net. Next, clean out the skimmer basket. When you fire up the pump, you want your skimmer to continue pulling as much debris out as possible.

Vacuum and Brush

If there is a lot of debris, algae, dirt or anything else on the bottom of the pool, opt for vacuuming to waste. While you’ll lose a little water, you’ll save a ton of time on cleaning your filter and reduce the amount of chemical you’ll need to rebalance.

Then get out your pool brush and do a good once over. If there are algae, this will loosen off the walls and expose to as much chemical as possible to kill it. If there are dirt and debris, the water may cloud but will get trapped in the filter.

Test the Water

Before you start adding chemicals to the water, you’ll need to check the balancing first. See where your Chlorine, pH and Alkalinity are. Odds are if you have things growing in the water, your chlorine will be low to non-existent. But still, check it.

Balance Total Alkalinity and pH

Balancing your chlorine will come in the next part. For now, just do some preliminary balancing. Start with your Total Alkalinity, and then fine tune the pH. As far as pH is concerned, you want it at 7.2 or above since you’ll be running the filter extensively. If the pH is too low, it can leach metals from equipment and lead to staining.

Killing Algae Fast

If you had little to no algae, then your pool should be looking pretty darn good by tomorrow by just letting your filter do the work. However if you’re in a rush, odds are you have algae in your pool. Luckily, this part should only take 15 minutes worth of work.



While you could kill the algae with chlorine alone, an algaecide will speed up the process while saving you money on chlorine. Not all algaecides are created equal (and we’re biased towards our own).

When time is a factor, we recommend using Swamp Treat™. Just add one bottle (1lb.) per 20,000 gallons. It’s our strongest algaecide and will give the fastest results. It also works independent of pH or Cyanuric Acid levels, it won’t stain, and works with just about any type of chlorine.

Whatever you decide to use, just make sure to follow the directions.


Now it’s time to shock the pool. It’s okay to use a heavy dose, depending on how much algae is present. It’s always better to use more than needed than less than needed – especially when trying to turn things around in one shot. Here are some rough estimates on what you should hit the pool with depending on the type of chlorine and gallonage of your pool (and assuming you’re using Swamp Treat™).

Pool Gallons1,0005,00010,00020,00050,000100,000
Liquid Cl (12%)1 quart1.25 gal2.5 gal5 gal12.5 gal25 gal
Liquid (10%)1.5 quart1.5 gal3 gal6 gal14 gal28 gal
Cal Hypo (65%)0.3 lbs1.6 lbs3.25 lbs7 lbs16.25 lbs33 lbs
DiChlor (56%)0.4 lbs2 lbs4 lbs8 lbs20 lbs40 lbs
TriChlor (90%)0.35 lbs1.75 lbs3.5 lbs7 lbs17.5 lbs35 lbs

Run that Filter

Now that you have the chemicals working, kick your filter on and let it run for 24 hours. Your filter is going to trap all that dead algae and get the pool clear. Just make sure to keep an eye on the pressure. When the pressure rises 10 pounds from when it was clean, backwash.

It’s going to take some time to kill everything, so call it day and get back on it in the morning.

Day 2 Finishing Algae Clean Up

You should be seeing a big difference today. Your pool should be blue and cloudy. Now it’s time to finish the job.

Check Filter

It’s likely the pressure has risen quite a bit since it’s been trapping algae all night. If needed, backwash and keep it running to clear the rest of the algae.

Vacuum to Waste

A good portion of that dead algae has probably sunk to the bottom of the pool. You could brush and let the filter keep removing it, but time is a factor. So vacuum it all to waste and let the filter continue to take care of the cloudiness in the water.

Test and Balance

You’ll need to see where the Total Alkalinity, pH, and Chlorine are at and adjust as necessary. Depending on the algaecide you used, you might need to shock again. If you used the Swamp Treat and our shocking recommendations, odds are your chlorine residual will between 3-5ppm – so no additional shock will be necessary however make sure to start balancing Total Alkalinity, and then pH. When you adjust Total Alkalinity, your pH will be affected too. Fine tune the pH only after you have your Total Alkalinity in range.


If you have a relatively small to moderate amount of algae, your pool should be ready to go after about 48 hours, or the end of the second day of clean-up.

If you have a more serious case of algae (where your pool looks like a swamp) it’s likely to take a couple more days to get the pool fully clear.

Just keep running your filter, backwash as necessary, add chlorine as needed, and you’ll be enjoying your pool in no time.