Description
Area/s of the surface feel rough to touch. Marks may resemble streaks that appear to flow downwards, sometimes towards the main drain, depending on the cause.
Colour
If in patches, usually looks slightly darker in colour in comparison to rest of the surface. If rough patches are lighter or dull in colour see Calcium Scale.
Possible Causes
Darker areas have been overexposed. This could be a result of:
- Acid being left too long on the surface during the acid wash/acid bath causing an excess of cement to be washed away which leaves remaining aggregate protruding from cement (over exposure of aggregate).
- Poor maintenance procedures – not diluting acid before adding it to the pool water. Acid is heavier than water. If undiluted acid is added to pool water the acid will sink to the bottom and overexpose the surface.
Solution
Areas of overexposure need to be sanded down using either wet and dry sandpaper or a rubbing stone. Be careful not to over rub the spot causing a lightening of the surface. Test first on a small unobtrusive area.
Ensure that any acid to be added to the pool is always diluted.