Scottsdale Pool Acid Wash Pebble and exposed-aggregate finishes: why acid is the wrong tool
This page is here because Scottsdale and Paradise Valley have a great many pebble and exposed-aggregate pools, and the single most damaging thing you can do to one is hire someone who treats it like plaster.
They are not the same surface
Plaster is a smooth cementitious coat. It is sacrificial by design, and an acid wash works by dissolving a thin layer off the top, taking the stains with it and leaving a fresh face behind.
A pebble finish is small stones set in a cement matrix, with the stones exposed at the surface. The stones are inert; the cement between them is what holds everything in place.
Acid does not distinguish. It attacks the matrix, not the pebbles. A light, controlled acid bath is sometimes used on these finishes. An aggressive acid wash of the kind that restores tired plaster will erode the cement between the stones, which leaves the surface rougher rather than cleaner, loosens pebbles, and eventually starts liberating them.
There is no putting that back. The remedy for a badly acid-damaged pebble finish is refinishing.
How to tell what you have, in ten seconds
- Smooth, uniform, single colour → plaster.
- Visible individual stones, textured underfoot, coarse to the hand → pebble or exposed aggregate.
- Somewhere in between, a fine consistent grit with sparkle → a quartz or aggregate-blend finish, which also should not be treated as plain plaster.
If you are not sure, photograph it close up and ask before anyone drains anything.
What actually works on pebble
Calcium and scale, which is the common complaint here because Valley water is hard: bead blasting. A fine abrasive under pressure removes the deposit mechanically without dissolving anything. It is the right tool for hard carbonate deposits and the only real option for silicate scale, which does not respond to acid at all. Calcium and scale removal is $200 to $500 and is priced separately from an acid wash for this reason.
Stains: chemistry chosen by stain type, not a surface strip. Do the vitamin C test first, described on the brown and rust stains page. Metal stains lift with ascorbic acid plus a sequestrant; organic stains respond to chlorine.
Algae: the same approach as any pool, with one honest caveat. A textured surface gives algae more purchase than smooth plaster does, so black algae on a pebble finish is harder to beat and needs more persistent brushing. On plaster the fallback is stripping the surface. On pebble that fallback is much more limited, which is a reason to deal with it early rather than letting it establish.
A full drain and clean without acid, at $200 to $450, which gets a pebble pool genuinely clean in most cases.
What an honest answer sounds like
If you send photos of a pebble pool and ask for an acid wash, we will tell you what it is and recommend blasting or a drain and clean instead. That is not turning down work; the calcium removal is real work and it is what you actually need.
And if the finish has already been acid damaged, with loose or missing pebbles and an eroded matrix, that should be said plainly too. It is a refinishing conversation and not something a cleaning company should be papering over.
What it costs
| Situation | What it needs | Price |
|---|---|---|
| Calcium or scale on pebble | Bead blasting | $200 to $500 |
| Heavy or silicate scale | Blasting, often per linear foot | Quoted |
| Stains on pebble | Targeted chemistry, by stain type | Your chemicals, or quoted |
| General grime, algae cleared | Drain and clean, no acid | $200 to $450 |
| Smooth plaster, stained | Acid wash | $400 to $800 |
| Matrix already eroded | Refinishing, not cleaning | A refinishing job |
From the pricing page.
Get a quote
Photograph the surface close up, close enough to see whether there are individual stones in it, plus a shot from the deck. That one close-up decides the method and therefore the price. We cover Scottsdale, North Scottsdale, South Scottsdale, Paradise Valley, Fountain Hills, Cave Creek, and Tempe.
Frequently Asked Questions
How do I know whether my pool is plaster or pebble?
Look and touch. Plaster is a smooth, uniform, single-colour surface, usually white or a solid tint. A pebble or exposed-aggregate finish has visible small stones set in a cement matrix and feels textured under your hand, like coarse sandpaper made of individual pebbles. If you can see and feel distinct stones, it is not plaster.
Can a pebble pool be acid washed at all?
Lightly and carefully, yes, and it is sometimes done. Aggressively, no. What holds a pebble finish together is the cement matrix between the stones, and acid attacks that matrix. Overdo it and you do not get a clean surface, you get a rougher one with loose pebbles and eventually pebbles coming out altogether. That damage is not reversible.
So how do you clean a pebble finish?
Bead blasting for calcium and scale, which removes the deposit mechanically without dissolving the cement around the stones. Chemical treatment for stains, chosen by stain type. And for algae, the same chlorine and brushing approach as any pool, with the caveat that a textured surface gives algae more to hold onto.
What does it cost?
Bead blasting and calcium work runs $200 to $500 depending on the area and how heavy the deposit is, with heavy scale often priced by linear foot. A full drain and clean is $200 to $450. A pebble pool should be quoted after someone sees it rather than from a table, because the finish condition decides the method.