Right Amount Of Algaecide For Pool? (One Helpful Guide!)

How Much Algaecide do I Add to My Pool?

Online pool calculators will tell you the amount of a pool chemical that you need to add based on pool volume and the current & target levels of the measure of pool chemistry such as pH level. However, Algaecides are not included in this online tool. So, what is the right amount of algaecide for pool?

As a rule of thumb, you need to add 2 ounces of algaecide per 10,000 gallons, during weekly maintenance. The amount should be increased to 4-8 ounces per 10,000 gallons on special occasions.

These are 1) after shocking the pool, 2) when opening the pool, 3) when closing the pool for winter and 4) when adding before rainstorms.

To get the amount of algaecide for your pool, simply multiply the above numbers (2 ounces for weekly and 4-8 ounces for special occasions) by your pool volume and divide by 10,000. You will get the right amount of algaecide that you need to add to your pool.

The volume (in gallons) for a rectangular pool  is estimated by multiplying 7.5 to the product of the length, width and average depth of the pool in feet. For a round or oval pool the multiplier is 5.9 instead of 7.5 and the diameter is used instead of length & width.

The average depth of a pool which is 2’ deep at the shallow end and 8’ at deep at the deep end is (2’ + 8’)/2 = 5’. The pool volume of a rectangular pool that is 40’X20’ will be (40 X 20 X 5 X 7.5) = 30,000 gallons. The pool volume of a circular pool with a 30’ diameter will be (30 X 30 X 5 X 5.9) =26,550 gallons.

Right Amount Of Algaecide for Pool

So, now you have a rule of thumb answer for what is the right amount of algaecide to add to your pool.

Check Dosage Instructions on the Packaging

You must, however, check the instructions on the packaging as different brands have different ingredients, strengths & dosage.

Recommended Dosage for Some Popular Brands:

Kem-Tek Pool and Spa 60-Percent Concentrated Algaecide

  • Start Up / Special Dose: 8 ounce per 10,000 gal.
  • Weekly Maintenance Dose: 2 ounce per 10,000 gal.

In The Swim Super Pool Algaecide

  • Start Up / Special Dose: 4 ounce per 10,000 gal.
  • Weekly Maintenance Dose: 2 ounce per 10,000 gal.

Aqua Clear 40032ACL Products Pool Algaecide

  • Start Up / Special Dose: 8 fl. oz. per 10,000 gal.
  • Weekly Maintenance Dose: 1.5 fl. oz. per 10,000 gal.

BioGuard Algae Complete

  • Start Up / Special Dose: 8 ounce per 10,000 gal.
  • Weekly Maintenance Dose: 1.5 ounce per 10,000 gal.

HTH 67032 Super Algae Guard Swimming Pool Algaecide Cleanser

  • Start Up / Special Dose: 4 ounce per 10,000 gal.
  • Weekly Maintenance Dose: 1 ounce per 10,000 gal.

Rx Clear Algaecide 60 Plus

  • Bi-Weekly Maintenance Dose: 4 ounce per 10,000 gal.

How Long Does it Take Algaecide to Work in a Pool?

You may add the right amount of algaecide to your pool and still not get the desired result. Wondered why? 

One of the reasons could be that all the algaecide has not been dissipated properly throughout the pool. To avoid this situation you should not pour all the liquid just in one spot. Especially if you have a large pool.

Walk around the perimeter of your pool and pour the liquid algaecide at several locations. Four to six locations will be good!

Make sure that you start the pool filter & pump before adding algaecide. Let the filter run for 2-4 hours, after adding algaecide, to ensure adequate circulation.

The best time to add algaecide is in the evening, at the end of the pool activity for the day. Your pool will be good to go, next morning. 

Most algaecides take about 24 hours to be fully effective but you can start using the pool much earlier. 

Most algaecides are also formulated to last for 5-7 days and keep the algae at bay. This is why it is very important to adhere to the routine of adding algaecide every week, during the pool season.

It is a good idea to buy the entire season’s requirements, ahead of time, so that you will not run out. You will also save some money when you buy in bulk. Just use a measuring cup so that you pour in the weekly dose.

Can you Put Too Much Algaecide in your Pool?

Putting a slightly higher quantity of algaecide, than that recommended by the manufacturer, will usually not result in any serious problems. 

However, you should not put excessive amounts. You will not kill the algae any faster if you doubled or tripled the algaecide dose. Remember algaecide’s primary role is to prevent algae growth, not to kill them.

If you have too much algae it is time to shock the pool (not increase algaecide dosage)!

You will know you have put in more than the right amount of algaecide when you see too much foam on your pool surface. The tiny foam bubbles are harmful to the filtration system and their efficiency will drop significantly.

Addition of algaecide, indirectly, results in lowering of pH level and increase of free chlorine (FC) level of your pool. More than the right amount of algaecide will make the pool water acidic.

Overdosing of algaecide and increase in pool acidity can also result in skin and eye irritation for the swimmers. The corrosive water will also eat away the metal parts, such as the filter and pool ladders, faster.

You have to be extra careful about not overdosing algaecide in your pool if you are using a copper based algaecide. Copper based algaecides are more effective and often necessary if you are dealing with black algae.

But copper based algaecides come with a few disadvantages. Overdosing can result in ugly green and black stains on the pool walls and floor. If not cleaned quickly, the stains can become permanent.

Copper algaecides are also responsible for turning blonde hair green!

How do I Fix Too Much Algaecide in my Pool?

If you have overdosed your pool with algaecide, the best solution is to wait it out for 2-3 days. The excess algaecide will get spent and will also dissipate more evenly throughout the pool.

In case there is excessive foaming on the pool surface you could scoop it in with a leaf rake and remove it from the pool. It will not solve the problem entirely but it will hasten the process of algaecide dissipation.

If you are in a hurry to use your pool then you can dilute your pool with fresh water. The best way to do this is to brush the pool thoroughly and then vacuum the floor. You should run the filter pump on the “waste” setting.

This method lets you kill two birds with one stone. Cleaner pool with the right amount of algaecide for your pool.

Thank you very much for reading the post. I do hope you found it informative and helpful.

Similar Posts