Adapt routine service and stain/chemistry care to the pool's specific interior surface: plaster, pebble, fiberglass, or vinyl

Steps

1. Identify the surface type before setting a chemistry target, since acceptable ranges and sensitivity to imbalance differ across surface types
2. For plaster and pebble (aggregate) finishes, keep LSI-style water balance tightly controlled, since these cementitious surfaces are directly vulnerable to etching (aggressive/low-LSI water) or scaling (high-LSI water)
3. For fiberglass, keep chemistry balanced primarily to protect the gelcoat finish and avoid abrasive brushing/cleaning tools that can scratch the gelcoat
4. For vinyl liners, avoid concentrated chlorine sitting directly against the liner (e.g., undissolved granular chlorine or tablets resting on it) and keep sanitizer levels within the liner manufacturer's tolerance, since vinyl can bleach/degrade from concentrated contact
5. Match cleaning tools to the surface — soft brushes on vinyl and fiberglass, stiffer brushes reserved for plaster/pebble finishes that tolerate more abrasion
6. Track surface-specific stain/etch history per pool so recurring issues (e.g., metal staining on plaster, liner discoloration) get addressed at the chemistry level, not just cosmetically