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Here are all the water test values and ranges you need to know to help ensure the water in your pool stays in tip top condition.

Total Alkalinity

Alkalinity holds the pH in place. If the alkalinity levels are low, it pulls the pH down causing the water to become acidic. Acidic water can corrode pool equipment, destroy pool plaster and cause bather irritation.

  • Concrete Pool 80 —125ppm
  • Fibreglass / Vinyl pool or spa pools 125—175ppm


Low pH can cause corrosion of equipment and pool surfaces, eye and skin irritation. Chlorine finds it hard to do its job if the pH is low. High pH can cause scaling on the pool surface and equipment. Chlorine finds it hard to work if the pH is high.

  • Concrete / Fibreglass / Vinyl pool or spa pools 7.4—7.6

Calcium Hardness

Water needs calcium. If we don't feed the pool calcium the water will draw it from where ever it can get it. This can cause pool surfaces to deteriorate and appear patchy. Excessive calcium on the other hand can be a cause of cause water cloudiness.

  • Concrete Pool ideal 200-275ppm
  • Fibreglass / Vinyl pool 125-175ppm
  • Spa pool 100-200ppm

Cyanuric Acid

A lack of Cyanuric acid in the water will cause chlorine loss. The Cyanuric acid acts as a sunscreen for the chlorine, preventing UV rays from drawing the chlorine out of the water before it does any work in the pool.

  • Concrete / Vinyl / Fibreglass pool 30-100ppm
  • Spa Pools n/a

Total Chlorine

Chlorine destroys bacteria in the pool water. A lack of total chlorine in a pool can therefore cause the water to become unhealthy.

  • Concrete / Vinyl / Fibreglass pool and spa pools 1-5ppm

Free Chlorine

Low Free Chlorine can cause water cloudiness and algae build up.

  • Concrete / Vinyl / Fibreglass pool and spa pools 1-5ppm

T.D.S. (Total Dissolved Solids)

When the TDS becomes higher than desirable, the chlorine can't become part of the water, causing cloudiness while also making the water unsafe to swim in.

  • Concrete / Vinyl / Fibreglass pool <2500
  • Spa Pools <1500

Metals (Copper & Iron)

  • Concrete / Vinyl / Fibreglass pool and spa pools 0