Swimming Pool Owners - Here's 8 Steps To Get Rid Of Blackspot Algae From Your Pool Forever

by Pool Builders on 06-30-2007 in Articles

Test your water

The only reason black algae has entered your pool is because of your lack of chlorine. To prevent black algae from sneaking up on you you must constantly check your water quality every day. You should be doing this anyway. You need to test for chlorine, ph, alkalinity, calcium hardness, stabilizer, etc. You may only be able to test for a small amount of these things from your home test kit. I do recommend you take a water Sample to your local pool store and get it professionally tested. Any decent pool store will be offering free water tests anyway.

Adjust your water

Once you know what your water is like you can then add the chemicals to adjust your pool to the correct levels. I can't go into whole lot of details in this article but I will tell you what your levels should be. I'm going to give you ballpark figures. This will depend on what type of surface your pool has, but you can use these figures below.

Chlorine 2.0-4.0

pH 7.4-7.8

Total Alkalinity 80-120

Calcium Hardness 200-500

Stabilizer 50-80

Add an algaecide

Blackspot algae is very chlorine resistant. You need to add an algaecide to the water to offer another angle of attack. AAlgaecides are specifically designed to kill and prevent algae. So it's a good idea to have an Algaecide in the water at all times. If you haven't got an Algaecide in the water now, you'd better put one in right away. Find one that is copper-based as they are usually the best ones to use. For best results pour the Algaecide directly on to the affected areas.

Shock the pool...

When shocking the pool with chlorine you must only use calcium hypochlorite or sodium hypochlorite. These 2 products are strictly chlorine and nothing else. You will need to know what size your pool is and follow the manufacturers directions to do this effectively. It is also a good idea to add your shock dose closest to the most affected areas.

Brush the walls

Because blackspot algae forms a protective barrier around itself you need to brush the affected areas really hard with a stiff brush. So that the added chemicals (chlorine and Algaecide) can do the job.

Circulate water better

Blackspot usually turns up in areas where there is lack of water circulation. Do your best to direct your water return jets in a way that moves the most amount of water around. I find that if you direct the jets to make the pool whirlpool the water around is the best way to go.

Attack black algae head-on

Like I said before...blackspot algae forms a protective barrier around itself. So you will have to regularly brush off the top of the algae and add your chlorine while it is exposed. Another great tip is to sprinkle chlorine granules directly onto the affected areas and let it sit and burn off the black spot. You can also rub a chlorine tablet onto the blackspot after you have brushed it. Make sure you wear gloves.

Rinse and repeat

Just keep testing and adjusting the water, scrubbing the blackspot and adding chlorine as close as you can get. And you will eventually get rid of it! And don't worry...It will go, but it will depend how bad the algae is as to how fast it will go. Water balance and scrubbing are the best thing you can do in this case.

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