Over time, pools can build up algae, stains and grime that regular cleaning won't remove. When the water has been green for a long time, or the surface is badly stained, a chlorine wash can bring the pool back to a clean, bright finish. Here's what a chlorine wash is, when you need one, and how it's done.
Chlorine wash vs. shock: what's the difference?
People often mix these up:
- Shocking means adding a large dose of chlorine to a full pool to kill algae and bacteria. It's the right first step for most green or cloudy pools. It's a big part of our green-to-clean service, and no draining is involved.
- A chlorine wash is done on an empty pool. A strong chlorine solution is applied directly to the walls and floor to kill algae and lift organic stains from the surface. Then everything is rinsed and the pool is refilled.
Most green pools can be recovered with shock, brushing and filtering, with no draining. A chlorine wash is for pools where algae or stains have soaked into the surface and won't come out any other way.
When a chlorine wash makes sense
- Long-term algae: a pool that sat green for months, where algae has stained the plaster.
- Organic stains: leaf, berry or other organic stains that don't respond to brushing and chemicals in a full pool.
- Before refinishing or repairs: cleaning the surface while the pool is already drained.
Metal stains (often brown, rust-colored or blue-green) usually need a different treatment. See pool stain removal.
Steps to chlorine wash a pool
1. Prepare
Remove leaves and debris, turn off the pump, and protect yourself. You'll need chemical-resistant gloves, eye protection and old clothes. Never mix chlorine with acid or other chemicals.
2. Drain the pool safely
Pump the water out with a submersible pump, following local rules for where pool water can be discharged. Keep the warning above in mind: in Florida, this step carries real risk to the pool.
3. Rinse and scrub
Hose down the walls and floor and scrub off loose algae and debris.
4. Apply the chlorine solution
Work in sections. Apply a mix of liquid chlorine and water to the walls and floor with a watering can or sprayer, then scrub it in with a pool brush. Leave it on for a short time; it does its work quickly.
5. Rinse thoroughly
Rinse each section well before moving on, so chlorine doesn't sit on the surface longer than needed. Pump out the rinse water from the deep end.
6. Refill and rebalance
Refill the pool right away. Once it's full, restart the equipment and balance the water: pH, alkalinity, calcium hardness and chlorine.
Keeping it clean afterward
- Keep the water balanced: test regularly and adjust pH, alkalinity and chlorine.
- Skim and empty baskets: organic debris feeds algae.
- Brush the walls and floor: regular brushing keeps algae from taking hold.
- Clean the filter: a dirty filter can't keep up.
- Shock after heavy use or big storms to stay ahead of algae.
The bottom line
A chlorine wash is a big job, and in Florida draining a pool comes with real risk. Before you drain, have a professional look at the pool. Many pools that look hopeless can be brought back without draining at all. Contact Sharkey Pools and we'll tell you honestly what your pool needs. Once it's clean, weekly service keeps it that way.
