Phosphate Remover and Algaecide Dose Calculator

Dose phosphate remover and algaecide from your pool volume and the rate printed on your own jug: fluid ounces, millilitres, quarts, and staged treatments. No signup.

What you are dosing

Product

Phosphate remover Algaecide

Two different jobs on the same pool. Phosphate removal strips the algae's food supply; algaecide is a backup to chlorine, not a replacement for it.

Pool volume

US gallons. Every label rate on this page is written per 10,000 gallons.

Unit

gal L

Phosphate label

How your label states the rate

Removal capacity Flat rate

Phosphate reading now

Orthophosphate, from a phosphate test kit or a shop water test.

Target

Leave at 0 to strip it out, or set the level you are happy to sit at.

Label capacity per 32 fl oz quart, per 10,000 gal

Read this off your jug. Published capacities range from about 2,000 to about 10,000 ppb per quart, so this field is the whole answer.

Advanced (label overrides)

Max phosphate dose per treatment, per 10,000 gal

Above this the precipitate drives filter pressure up, so the dose is split across visits.

Add to the pool

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Rate applied: —
Dose: —

Label rate → pool volume → dose

Quantity estimate, not a water-safety or compliance record. Phosphate removers and algaecides are dosed by their own labels, and the label on the jug governs.

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How this is calculated

Every rate on this page is stated per 10,000 US gallons, so the pool volume is a plain multiplier. What changes between the two faces is where the rate comes from.

pool_multiple = volume_gal / 10000

Phosphate, removal-capacity basis:
  ppb_to_remove  = max(0, reading_ppb − target_ppb)
  ppb_per_fl_oz  = label_capacity_ppb_per_quart / 32
  dose_fl_oz     = ppb_to_remove / ppb_per_fl_oz × pool_multiple

Phosphate, flat label rate:
  dose_fl_oz     = label_rate_per_10k × pool_multiple

Algaecide:
  strength_factor = label_strength_pct / your_strength_pct   // 1 for copper
  dose_fl_oz      = label_rate_per_10k × strength_factor × pool_multiple

Phosphate staging:
  cap_fl_oz      = max_per_treatment_per_10k × pool_multiple
  treatments     = ceil( dose_fl_oz / cap_fl_oz )

Worked example, phosphate. A 20,000 gallon pool reading 1,200 ppb, dosed to zero with a product whose label says one quart removes 10,000 ppb per 10,000 gallons. One fluid ounce therefore removes 312.5 ppb, so the rate is 3.84 fl oz per 10,000 gallons and the pool takes 7.68 fl oz. The per-treatment cap of 8 fl oz per 10,000 gallons is 16 fl oz on this pool, so it goes in as one treatment. Swap in a product rated at 2,000 ppb per quart and the same job takes 38.4 fl oz, which is five times the liquid and three staged treatments.

Worked example, algaecide. The same pool at the Polyquat 60 weekly-maintenance midpoint of 3 fl oz per 10,000 gallons takes 6 fl oz. If the jug on the truck is a 30% polymer rather than a 60%, the strength factor is 2 and the dose becomes 12 fl oz.

Why the label rate is an input and not a constant. Phosphate removers do not share a dose. Published removal capacities run from 2,000 ppb per 32 fl oz treatment per 10,000 gallons, Pool Breeze's published claim, to 10,000 ppb per quart per 10,000 gallons, Orenda's figure for PR-10,000. That is a five-fold spread, so any calculator that hard-codes one rate is wrong for most of the shelf. The 10,000 ppb preset here is the Orenda figure, and it is editable, as is every other number on the page.

The staging cap. 8 fl oz per 10,000 gallons in a single treatment is Orenda's published recommendation, and the reason is mechanical: the precipitate lands on the filter and raises pressure. Above that, dose across visits or plan to vacuum the fallout and clean the filter the next day.

Algaecide bands. The presets are the published Polyquat 60 label directions: 2 to 4 fl oz per 10,000 gallons weekly, 6 to 11 for an initial or preventative dose, 11 to 17 against visible algae. The presets seed the midpoint of each band. Strength scaling is offered for polymer and quat chemistries, where the rate is tied to an active percentage, and switched off for copper, which is dosed to a metal residual instead.

Sources: Orenda Technologies, How to Use PR-10,000 (one quart removes approximately 10,000 ppb of phosphates in 10,000 gallons; single treatment limited to 8 fl oz per 10,000 gallons because the precipitate increases filter pressure; water clouds in seconds when phosphates are present). Pool Breeze Phosphate Remover (one 32 fl oz treatment removes 2,000 ppb in 10,000 gallons, the low end of the range). Published Polyquat 60 label directions for the three dose bands, as carried by the retailer listing: the registered EPA label for this product is a scanned image and not machine-readable. Pool Operation Management (copper is not stable in the presence of chlorine and can stain; quats foam in agitated water; polymeric quats do not foam and contain no metals). Volume converts with 1 US gallon = 3.785411784 L and 1 fl oz = 29.5735295625 mL.

Two products, one piece of arithmetic. Phosphate removers and algaecides are both dosed as a rate per 10,000 gallons, so once you know the pool volume the only real question is what rate, and that comes off the label rather than out of a calculator. This page does the scaling, shows the rate it used, and leaves every number you can argue with editable.

Why the label rate is an input here and a constant everywhere else

Most phosphate calculators on the web hard-code a dose. That is a defensible choice for chlorine, where a pound of 65% cal-hypo raises free chlorine by a known amount whoever bagged it. It is not defensible for phosphate removers, because they are not the same product in different packaging. Published removal capacities run from 2,000 ppb per quart per 10,000 gallons at one end of the shelf, which is Pool Breeze’s published claim for a 32 fl oz treatment, to 10,000 ppb at the other, which is Orenda’s for a quart of PR-10,000. A calculator that picks one and calls it the dose is wrong by a factor of five for most of the products a route truck actually carries.

So this tool asks. Enter what your jug says it removes, or switch to the flat-rate basis if your label gives a weekly maintenance rate instead, and the volume scaling follows. The 10,000 ppb preset is Orenda PR-10,000’s published figure and is labelled as such, not presented as the dose.

The filter is the real constraint

The chemistry of a lanthanum-type remover is fast and unfussy: it drops phosphate out of solution. Where it bites is downstream. The precipitate goes onto your filter media, and Orenda publishes a recommended maximum of 8 fl oz per 10,000 gallons in a single treatment for exactly that reason, unless you are coming back the next day to vacuum the fallout and clean the filter. The calculator scales that cap to the pool in front of you and reports the dose as treatments rather than as one number you were never going to pour in anyway.

Expect the water to cloud within seconds of dosing if phosphates are present. That is the reaction, not a fault, and it is why the visit plan matters more than the dose: filter running, pressure watched, clean scheduled.

Algaecide, and the three things that change the dose

Algaecide rates are banded rather than fixed, and the bands are wide. The published Polyquat 60 label directions give 2 to 4 fl oz per 10,000 gallons for weekly maintenance, 6 to 11 for an initial or preventative dose, and 11 to 17 against visible algae. Those are the presets, seeded at their midpoints, and they are the starting point of a conversation with your own label rather than the end of one.

Three levers move the answer:

Chemistry. Polymeric quats do not foam and contain no metals. Ordinary quats are surfactants, so they foam in agitated water and the residual is short-lived, which is why they are topped up weekly. Copper kills fast but is not stable in the presence of chlorine, which can oxidise it into stains on pool surfaces, and once copper is in the water dilution is the only way back out.
Strength. A 30% polymer needs twice the volume of a 60% one for the same active dose. The calculator scales between the percentage your rate assumes and the percentage on the jug, and switches that lever off for copper, which is dosed to a metal residual instead.
What you are treating. Prevention and a visible bloom are different doses of the same jug, which is what the three bands are for.

Where this sits in the visit

This page is deliberately narrow: two products, one dose each. The sanitiser, acid, alkalinity, calcium and stabiliser side of the same test result belongs to the pool chemical dosing calculator, which sequences them in the order they have to go in. A pool that is already green is a chlorine problem before it is a phosphate problem, and the green pool recovery calculator handles that sequence. Every rate on this page is scaled by the pool volume, so if you are guessing at that figure, fix it first with the pool volume calculator. The wider map of how these parameters pull on each other is the pool water chemistry hub.

Nothing is saved: no customer record, no dosing history, no account. This is a quantity estimate rather than a water-safety or compliance record, and the label on the jug governs the dose, the handling and the wait before anyone swims.

Frequently asked questions

How much phosphate remover do I need per 10,000 gallons?

There is no single answer, and any calculator that gives you one is guessing on your behalf. Published removal capacities run from about 2,000 ppb to about 10,000 ppb per 32 fl oz quart per 10,000 gallons depending on the product, a five-fold spread, so the figure on your own jug is the whole calculation. Enter it and the arithmetic is quick: a 20,000 gallon pool reading 1,200 ppb, dosed with a product rated at 10,000 ppb per quart, takes 7.68 fl oz. The same job with a product rated at 2,000 ppb per quart takes 38.4 fl oz.

Why does the calculator split a big phosphate dose across treatments?

Because the filter, not the chemistry, is the limit. Lanthanum-type removers work by dropping phosphate out of solution as a precipitate, and that precipitate lands on your filter media and drives pressure up. Orenda publishes a recommended maximum of 8 fl oz per 10,000 gallons in a single treatment unless you are returning the next day to vacuum the fallout and clean the filter. The calculator scales that cap to your pool and shows how many treatments the dose becomes, so a 96 fl oz job on a 20,000 gallon pool reads as six treatments rather than one very bad afternoon.

How much algaecide per 10,000 gallons?

It depends on the chemistry and on the dose you are giving. The published Polyquat 60 label directions are 2 to 4 fl oz per 10,000 gallons weekly for routine maintenance, 6 to 11 fl oz for an initial or preventative dose, and 11 to 17 fl oz against visible algae. Those three bands are the presets above, seeded at their midpoints, and every one is editable, because copper blends and ordinary quats are dosed differently again and your label is the authority.

Does the strength percentage on the jug change the dose?

For polymer and quat chemistries, yes, and by a lot. A 30% polymer needs twice the volume of a 60% one to put the same active into the water, so a 6 fl oz job becomes 12. Enter both percentages, the one the rate assumes and the one you are holding, and the calculator scales between them. Copper is the exception: copper products are dosed to a metal residual in the water rather than to an active percentage, so the strength lever is switched off for them and your rate is used as written.

Will phosphate remover clear a green pool?

No. Phosphate removal takes away the food supply, which is prevention; it does not kill algae you can already see, and dosing it into a green pool mostly means dosing a filter that is about to be overwhelmed anyway. Kill the algae first with chlorine, which is what the green pool recovery calculator sequences, get the water clear, then strip the phosphates so it does not come back. Expect the water to cloud within seconds of dosing when phosphates are present: that is the product working, not a fault.

Is algaecide a substitute for chlorine?

No, and treating it as one is the most expensive habit in pool care. Algaecide is a backup that slows algae between visits; sanitiser is what actually keeps the water safe, and a pool running on algaecide alone is an unsanitised pool that happens to look clear. Dose the chlorine, acid, alkalinity, calcium and stabiliser side of the same visit with the pool chemical dosing calculator.

Sources

How to Use PR-10,000: dose bands by phosphate level and a recommended maximum of 8 fl oz per 10,000 gallons in a single treatment, because the resulting precipitate can increase filter pressure. Orenda Technologies. Retrieved Sep 11, 2026.
PR-10,000 Frequently Asked Questions: recommended maximum dose of 8 fl oz (0.24 L) per 10,000 gallons (38,000 L) at a time. Orenda Technologies. Retrieved Sep 11, 2026.
How to Use PR-10,000 (help centre): one quart (32 fl oz / 0.94 L) of PR-10,000 removes approximately 10,000 ppb of phosphates in 10,000 gallons (38,000 L) of water, with a single-treatment limit of 8 fl oz per 10,000 gallons. Orenda Technologies. Retrieved Sep 11, 2026.
Pool Breeze Phosphate Remover: one 32 fluid ounce treatment will effectively remove 2,000 ppb in 10,000 gallons of water, the low end of the published capacity range. Pool Breeze (label claim as published by Pool Geek). Retrieved Sep 11, 2026.
ProTeam Polyquat 60 algaecide, published label directions: initial 6 to 11 fl oz per 10,000 gallons, routine maintenance 2 to 4 fl oz per 10,000 gallons weekly, visible algae 11 to 17 fl oz per 10,000 gallons. ProTeam (label directions as published by EZ Pools). Retrieved Sep 11, 2026.
Understanding Algae Prevention and Common Algicides: copper is not stable in the presence of chlorine and can be oxidised into surface stains, quats foam in agitated water, polymeric quats do not foam and contain no metals. Pool Operation Management. Retrieved Sep 11, 2026.

How we choose and check our formulas