How to Clean Calcium Off Pool Tile at the Waterline

Pool tile picks up a white band right at the waterline where splash and evaporation leave calcium behind, and the band gets thicker every summer. Pool stores sell acid washes for it, and companies will bead-blast it for a few hundred dollars. If the scale is not years thick, there is a middle path that works well for most pools: a mild abrasive paste, a pad on a low-speed drill, and an afternoon.

Before you start

Lower the water level a few inches below the scale line if you can, so you are working on dry tile. Check the tile: glazed ceramic and porcelain tile handle a mild abrasive well. Glass tile also does, but test one tile first. Natural stone coping is softer and should be done by hand with a pad rather than a buffer.

What you need

• A gallon of A-MAZ Water Stain Remover for a full pool; a 14 oz jar covers a spa or a small section. The formula has no acid, so it is safe around the pool and the plants.
• Gripper Pads. A pad fits a drill sanding-disc attachment, and a light-duty pad on a low-speed drill is the fastest way to cover a long tile line.
• A spray bottle of water, a bucket, and a stiff hand brush for the grout lines
• Ultra Gloss Sealant for after

Step by step

1. Wet the tile and apply the paste. Spread a layer of paste along a three-foot run of the scale line.
2. Buff on low speed. With the pad on the drill, keep it flat against the tile and move steadily along the line. Keep the paste moist with the spray bottle; the paste does the work, the pad just carries it. Do not press hard or run the drill fast, which heats the tile and does nothing for the scale.
3. Get the grout by hand. Scale settles into the grout lines. A scrubber pad or stiff brush with a little paste cleans them.
4. Rinse into the pool. The residue is calcium and paste; a hose rinses it away. Move to the next run.
5. Seal the tile. Once the whole line is clean and dry, rub Ultra Gloss Sealant along the tile and grout with a cloth. Sealed tile sheds water and takes far longer to build a new line. Reseal at the start of each season.

When to call a pro instead

If the scale is a thick, hard crust that has been building for many years, especially on a pool with very hard fill water, a buffer will be slow going. That is when bead blasting earns its price. For the more common case, a line that has built up over a season or two, the paste and pad method takes a couple of hours and costs a fraction of the alternatives. Customers use the same approach on the tile in a spa, on fountain edges, and on the glass of a pool-side railing.