Notification
Phosphate Pool Water Calculator
Phosphate is algae's favourite food. Use our Phosphate Water Calculator to see what your test strip result means, and exactly how much Phosphate Remover to dose.
How to Use Your Phosphate Test Strips
Takes about 30 seconds. Read the result at exactly 15 seconds for accuracy.
Collect a water sample
Fill the included 10 mL test tube with pool water. Take it from elbow depth, away from the skimmer and return jets.
Dip the test strip
Fully submerge the reagent pad into the water in the tube. Do not shake off the excess. Let it drip naturally.
Invert and wait 15 seconds
Flip the strip upside down in the tube so the pad stays in the water. Start your timer and read at exactly 15 seconds. Reading too late gives a falsely high result.
Match the colour
Hold the strip against the colour chart on the bottle. Match in natural daylight, not under yellow indoor lighting. Choose the closest colour below.
Enter your result below
Select your pool volume, then tap the strip colour that matches. We'll tell you exactly what to do next.
Pro Tip: Store strips in the sealed bottle with the lid tight. Moisture is the number one reason strips give inaccurate readings. Keep them out of direct sunlight and away from hot storage areas.
We need your pool size to calculate the correct dose of Phosphate Remover.
2. Match Your Test Strip
๐ Tap the colour that matches your strip
Values shown as ppb (parts per billion) with equivalent ppm underneath.
3. Analysis & Dosage
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Select your phosphate level to see how much remover to dose.
Phosphate Control Essentials
You cannot fix what you cannot measure. Test fortnightly and dose to keep phosphate under 100 ppb.
Why Phosphate Matters
Phosphates are a food source for algae. Even if your chlorine is perfect, high phosphate levels mean any algae that lands in your pool can bloom fast. This is why pools that always go green usually test high for phosphate.
Understanding ppb vs ppm
1 ppm = 1000 ppb. Pool phosphate is measured in parts per billion (ppb) because the levels that matter are tiny. Even 0.3 ppm (300 ppb) is enough to feed an algae bloom. The bottle chart shows ppm, but we display both so you can match either scale.
- 0 to 100 ppb (0 to 0.1 ppm): Ideal. Algae has nothing to feed on.
- 100 to 300 ppb (0.1 to 0.3 ppm): Acceptable but monitor. Dose remover if you have had algae before.
- 300 to 1000 ppb (0.3 to 1.0 ppm): High risk. Treat with Phosphate Remover.
- 1000+ ppb (1.0+ ppm): Severe. Algae will keep returning. Treat, then re-test in 48 hours.
Common phosphate sources: fertiliser runoff, leaves and garden debris, some tap water, and cheap pool chemicals.
Phosphate & Algae FAQ
Stop Feeding the Algae
Grab the Phosphate Test Strips and Phosphate Remover and break the algae cycle for good.
Shop Phosphate Test Strips