The surface decides how much your water cares about calcium and how forgiving it is of mistakes.
Plaster / gunite
The classic cement-based finish — durable, but it needs calcium.
A hard cement-and-aggregate shell (often called gunite or shotcrete with a plaster coat). The most common in-ground surface, and the most chemistry-sensitive.
How it changes upkeep- Cares about calcium hardness: soft, calcium-starved water slowly etches plaster, so this surface wants calcium kept in range.
- Sensitive to low pH, which can etch and roughen the finish over time.
- Benefits from regular brushing, especially when new, to prevent staining and scale.
Fiberglass
A smooth molded shell that is easy on chemistry.
A one-piece molded shell with a gelcoat surface. Non-porous and smooth, which makes it forgiving and low-maintenance.
How it changes upkeep- Far less fussy about calcium than plaster — the surface does not need calcium to protect itself.
- The smooth, non-porous surface resists algae, so it often needs less brushing and scrubbing.
- Still cares about pH and sanitizer; very high pH or imbalanced water can chalk or stain the gelcoat.
Vinyl liner
A flexible printed liner — gentle chemistry, but mind sharp swings.
A flexible vinyl sheet that lines the pool shell. Common in above-ground and many in-ground pools, and the most affordable to install.
How it changes upkeep- Does not need calcium to protect a surface, so low calcium is less of a concern than with plaster.
- Liners can wrinkle, bleach, or become brittle from chronically low pH or strong, undissolved chemicals dropped on them — pre-dissolving matters here.
- Avoid letting granular chlorine sit on the liner; it can bleach a permanent spot.
Tile
Premium and long-lasting — watch the grout and scale line.
A fully tiled interior (or a tile waterline band on other surfaces). Beautiful and durable, with grout that needs attention.
How it changes upkeep- High calcium or high pH shows up first as a chalky scale line at the waterline.
- Grout can stain or erode if water chemistry runs aggressive, so steady balance pays off.
- Regular waterline wiping keeps the tile looking its best.
Every option here is really a chlorine pool underneath — the difference is how the chlorine gets there and how much you handle yourself.
Traditional chlorine
You add the chlorine; you have full control.
A pool sanitized by chlorine you add yourself — liquid, granular, or tablets. The most common and most flexible system.
How it changes upkeep- You top up chlorine regularly; the upside is precise, immediate control.
- Cyanuric acid (stabilizer) matters a lot for outdoor pools so sunlight does not waste your chlorine.
- No specialized cell to maintain — just consistent testing and dosing.
Saltwater (salt-chlorine generator)
Still a chlorine pool — it just makes its own from salt.
A pool with a salt-chlorine generator (SWG). Dissolved salt passes through a cell that converts it to chlorine continuously, so you add salt instead of chlorine day to day.
How it changes upkeep- You maintain a salt level in the cell’s target window instead of dosing chlorine manually.
- The cell needs periodic inspection and occasional cleaning of calcium scale to keep producing.
- Still needs the same balanced pH, alkalinity, and CYA as any chlorine pool — saltwater is not chemistry-free, just lower-effort sanitizing.
Bromine
An alternative sanitizer, most common in spas and indoor pools.
A sanitizer related to chlorine that stays effective at higher temperatures and higher pH, which is why it is popular for hot tubs and some indoor pools.
How it changes upkeep- Holds up better than chlorine in hot water, so it suits spas and warm indoor pools.
- Is not stabilized by CYA, so it is generally used indoors or in covered water out of direct sun.
- Tends to be gentler-smelling for some swimmers, at a higher running cost than chlorine.
