Symptoms:
- Surface appears patchy or blotchy – apparent loss of colour.
- May feel sharp or abrasive to touch
- Unable to remove algae with chlorine.
- Also apparent on tiles and or pool fittings.
- Colour – usually white but can be discoloured (brown, grey or green) if dirt, metals or algae have plated out at the same with the scale.
Cause:
The following either happen on their own or in combination:
- High pH level causing the calcium in the water to precipitate out of solution and plate onto the surface.
- Calcium levels out of recommended limits
- High water temperature.
Solution:
If scale hasn’t been on the surface for too long, lower the pH to between 6.5 and 6.8 (using hydrochloric acid). Leave at this level for approximately 1 week and brush the affected areas over the duration to remove the scale. Take a water test and balance accordingly. Monitor the surface texture of the pool daily. If the surface becomes rough over exposure may occur. To prevent over exposure, increase the pH with pH increaser as soon as excessive roughness is detected.
After performing this procedure, it is imperative that calcium levels in the water are returned to recommended levels (200 – 250 ppm). Failure to do so could cause excessive acid demand which in turn will weaken the surface and may lead to other problems.
If scale has been on the surface for a number of months then the pool will most likely have to be drained and acid washed, then filled up and re-balanced. Experienced pool technicians may add acid (10 – 15 L for average 50,000L pool) to the pool the day before it’s drained to soften the calcium. The pool is then drained and using a high pressure cleaner, the calcium is water blasted off. The pool is then refilled and rebalanced.
To avoid future calcium scale occurrences, maintain Cal-Stop™ in your pool water. This can be achieved by purchasing a bottle of Cal-Stop™ from your local pool shop every 6 months. Cal-Stop™ keeps calcium in solution even if the pH level does increase. If your local pool shop doesn’t stock Cal-stop then please call River Sands on (07) 3287 6444 Brisbane callers or 1800 077 744 Toll Free for supplier near you
FACT SHEET – HIGH CALCIUM LEVELS
SYMPTOMS:
• High acid demand
• Cloudy water
CAUSES:
• Excessive amounts of acid have been added to the pool causing calcium to be drawn out of the cement.
• Aristone™ is curing (first 8 weeks after installation) – calcium is a byproduct of cement curing.
SOLUTION:
• Partially drain pool to dilute high calcium content and bring back to between 200 – 250 ppm. Repeat until desired levels are achieved. Rebalance Total Alkalinity, pH and add Cal-Stop™.