A How To Guide On Swimming Pool Phosphate Removers & Algaecides

The year of 1994 was a very special year for the pool industry, a keen pool enthusiast by the name of Dudley John Mills approached Lo-Chlor, the leading chemical manufacturer in Australia and put forward his findings of a white milky substance, which revolutionised the way the pool and spa industry treat water forever!

Twenty plus years later, the milky substance now commonly known worldwide as “phosphate remover” or “algae starver” is the single, highest-selling specialty chemical in the Australian pool industry and almost every chemical company across the globe has some form of phosphate remover in its range to combat long-term algae problems and stubborn algae strains.

What are Phosphates and Nitrogen

Phosphorous is a mineral and nitrogen is a gas. The two most significant problems associated with phosphorus and nitrogen are moderate to severe algae blooms and a much higher chlorine demand. Both these elements essentially create a recipe for any algae to bloom, eat and thrive in swimming pools.


Phosphates typically enter the pool from a range of garden products, plant debris and rain. Phosphates can also come from dead skin cells, body fats and oils and residue on the skin from soaps and hair treatments.

The main ways of phosphates finding their way into the pool are:

  • The wind blows dirt into your pool
  • Sprinkler run off from your lawn or landscaping enters your pool
  • Leaves, twigs, or bark enters your water


Nitrogen can also come into your pool from garden products, but more typically, it’s introduced through humans! Sweat is the main culprit (when swimmers don’t shower before using the pool) or during physical activity while in the water the body still omits sweat into the water. And no surprises here, Urine! This is when swimmers don’t use the facilities before going into the pool.

High phosphates and nitrates use all of chlorine that kills bacteria and algae, thereby causing a much higher chlorine demand. You will have a difficult time maintaining chlorine levels, while algae will thrive, the water will become cloudy, and the pool will look horrible.

The only way to remove nitrates from the water is to drain and refill with fresh water, or regularly backwash your pool to ensure levels are maintained and more importantly (because you cannot treat nitrates) that the nitrates are periodically removed from the pool water!


Phosphates in swimming pool water, even at low concentrations, can cause accelerated algae growth in poorly maintained pools.

Pools that are properly maintained and kept in chemical balance usually do not have difficulty controlling algae, but the presence of phosphates can make algae control more difficult to control, and you’ll need to increase the amount of sanitiser to maintain satisfactory control of algae.

Keeping your pool properly balanced and sanitized is the key to keeping all forms of algae from growing.

Key points to eliminate algae:

  • Keep your pH, alkalinity and sanitizer levels in the correct range at all times.
  • Run your pump and filter for 8 to 12 hours to ensure water turn over
  • Keep your pool clean by regularly vacuuming and brushing.

Phosphate Removes vs Algaecides

Phosphate removers are not algaecides. One mistake a lot of people make is that they see a green pool or black spot algae and they start their treatment with a phosphate remover. This is not the correct way to manage the problem and is a waste of money.

In a Nutshell: Phosphate removers will not clear up green pools and they do not kill algae!

Algae thrives on the phosphates as their food source, so if there are algae present in the pool, you can be certain the phosphate level is low or even zero. This is because the algae have actually consumed the phosphates as they are using them as a nutrient to survive.

Fact: This is a key process in understanding long-term algae prevention.

So how do we treat algae strains correctly and how do we ensure the long-term prevention of these strains?

  • As with the black spot and mustard algae, using straight chlorine or cheap algaecides will give you superficial results. The algae will return in a short amount of time and you will have dissatisfied customers.
  • Copper-based algaecides are very good for a vast array of algae types and will give you long-term algae prevention after the algae has been
  • These are non-copper alternatives that provide a fantastic result when treating green algae in particular.

This is the ideal time to hit them hard with a bulk phosphate remover that removes high-levels of phosphates at the start of the process.

Fact: Sixty percent of pool owners experience two full algae blooms every season. So, what causes these blooms and how can we prevent them?

Pool Phosphate Treatment

  1. Test for phosphate levels
  2. Vacuum any debris out of the pool prior to treating
  3. Backwash your pool filter thoroughly
  4. Apply phosphate remover per label dosage rate specified
  5. Run filter for 48 hours
  6. Backwash pool filter
  7. Retest for phosphate levels. If necessary, repeat steps 3-5

SEE ALSO: Do we need phosphate removers for winter?

Pool Phosphate Removal Tips

  1. Before testing for phosphates, water should be balanced, and chlorine level below 5 ppm.
  2. Algae should be treated and pool clean before testing and treating phosphates.
  3. Correct the source of the phosphate contamination, or use weekly maintenance dosage.
  4. After treatment with phosphate remover, filter pressure will rise. Backwash as needed.
  5. Small or ineffective pool filters may benefit from using a clarifier after treatment.
Pool Phosphate Removal Tips

Further prevention with regular pool maintenance.

Ongoing regular pool maintenance can also eliminate the bloom and spread of algae in all pools, basic monthly tasks to help this are:


Remember, phosphate remover is for prevention and algaecide is for treatment of algae. If you already have algae, it's time to breakout the algaecide. If there's no sign of algae but you're starting to get phosphate levels, treat your pool water with some phosphate remover.

Products Featured on This Blog Post

Want an extra layer of protection to your pool? Consider replacing your cartridge filter with an antimicrobial filter cartridge, not only will your pool be algae-free, but it will be germ free as well!

Do you have any questions about this topic or the featured products? No worries, we're here to help! Drop us a question down below and we'll get back to you ASAP.

Happy swimming :)

We Need This
We Need This
We Need This
Please validate your form with reCAPTCHA.
Thank you!

Leave a comment

All comments are moderated before being published