Algae Removal From Swimming Pool

Start with a test kit.

Listening to strangers online is a great way to waste money.  Use the kit to establish baseline facts about the pool, and go from there.

When going green to clean, get your pH into the range where chlorine will work effectively.   This is 7.4 - 7.6 where chlorine will be 50% available.  If the pH is way above 8.0, you’ll be adding sanitizer to the ends of the earth.

CYA matters; so I’ll mention it for the haters. There, now, let’s move on.

30ppm of Chlorine will kill off all algae spores.  The kicker is to maintain it long enough that you can brush, circulate, and maintain it for a few hours so the algae goes gray.

Liquid Chlorine can work; it’s only 12% concentration in the bottle.  CalHypo can range from 60 percent on up.  I’d avoid stabilized chlorine (trichlor) yea it is 99% but it’s tied to CYA - there I said it.

Brush, brush, brush, brush.  If you want to spend more, so use a phosphate remover.  But do so prior to starting the process.

Rinse the gunk from the filter. Watch chlorine every 1/4 hour for any major reductions, and continue to add until it settles into compliance.

You’ll be algae free.  Protip, reduce the pH to 7.2 to get a bit more bang for the buck. But, it will sink more as it dies off and can be a bit more hazardous.

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Never mix chlorine and acid together outside of the pool.

This will create hazardous gasses that will ruin your day.

Have sodium bicarbonate on hand in case you spill acid.

Have thiosulfate on hand in case you spill chlorine.

Again, don’t be afraid to brush. The cell walls must come into contact with sanitizer. If the stuff is thick, you’ll work at it a bit, —- You may achieve faster results later in the day or earlier morning due to lower UV light (chlorine’s nemesis) again CYA is there to protect. If it is ravenously high; life is not as fun.

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That didn’t work?

Test CYA:  this should never exceed 7.5% of the CYA test result.  If you get into the 150+ range, you need substantially more chlorine to achieve 30ppm, or drain some water and replace.

Example: CYA 250 - you need a base of 18.75ppm chlorine to reach useful   + 30ppm for a total of 48.75 or 50.  To achieve that in a 15,000 gallon pool;

10.7 x 1.5 x 50 is about 63 gallons of liquid chlorine. It could get really costly.

2 x 1.5 x 50 / 16 about 10 pounds of CalHypo

The middle number is 10,000 / pool size in gallons. This dosage is normally on the chemical label.

The concentration matters. All chlorine has dosage instructions on the label. Follow them.

That’s where you’ll need to do the math.  In my area. A 4 pack of chlorine is $15 x 15 boxes is about $225

$4 a pound for CalHypo

Wear eye protection. Keep your hands out of the water until chlorine drops below 10ppm per CDC safety guidelines. Refer to SDS sheets for safety information. Don’t mix chemicals, ensure you have a source for safe water in case of eye contact and a clear area to run if something goes wrong.  Clear the area.

Do the math/chemistry.  Show us your results. It should start to visibly clear within hours.

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Article written by Jason Davies