Why a Pool Turns Green and What It Takes to Bring It Back

A pool can go from sparkling to swamp in a few days. Anyone who's lived in the Valley through a long summer has either seen it happen or heard about a neighbor's pool that got away from them. The good news is that green water is almost always recoverable. The better news is that understanding why it happens makes it much less likely to happen to you.

Why green happens so fast here

Green water is algae, and algae needs three things: warm water, food and not enough sanitizer to stop it. Desert heat supplies the first with no effort. Warm water also speeds up everything that eats sanitizer, so the protection you had on Monday can be gone by the weekend. Sun, swimmers, dust and debris all draw down the chlorine, and when it runs out, algae can bloom quickly.

The usual triggers are ordinary ones. A pump that stopped circulating because of a tripped breaker or a failed timeclock. A filter so loaded that water barely moves through it. A storm that dumped dirt and organic matter into the water. A salt cell that quit making chlorine without anyone noticing. A house that sat empty for a few weeks, or a pool nobody was watching during a vacation or a move. Most green pools trace back to one of these, not to bad luck.

Why shocking it yourself often disappoints

The instinct is to dump in a lot of chlorine and wait. Sometimes that works on a mild case. On a heavy bloom it often fails, because the water chemistry is out of balance and the filter is clogged with dead algae. Chlorine works poorly when the water isn't balanced, and a loaded filter keeps recirculating what you're trying to remove. You can end up spending more on product than the recovery would have cost, with the pool still green.

If you catch it early, keep the pump running, empty the baskets, brush the surfaces and get the water tested. The sooner someone looks at it, the less work the fix takes. Waiting a week usually turns a cheap problem into a bigger one.

What a green-to-clean recovery involves

Mountain Ridge Pool Service's Green to Clean is a one-time recovery, and the steps depend on how far the pool has gone. It starts with chemical treatment and balance, which means testing the water, correcting what's out of range, and treating the algae. For many pools, this plus some filter work is all it takes.

• Chemical treatment and balance, to kill the algae and correct the water
• Draining the pool, when the water is too far gone to treat in place
• A chlorine bath, to sanitize the surface once it's empty or low
• An acid wash, to remove stains and growth left clinging to the surface

When a pool has sat green for a long time, treating the water in place can mean fighting a lot of dead organic material, and starting over with fresh water is cleaner and often faster. Draining opens the door to the chlorine bath and the acid wash, which deal with what's left on the plaster. An acid wash takes off a thin layer of the surface, so it's something to have done by someone who knows what the plaster can take, not a weekend experiment.

Not every pool needs every step. A pool that's lightly green might need only treatment and balance. A pool that's black-green and has been neglected through summer may need the full sequence. That's why quotes for this kind of work vary, and why a price given without seeing the pool should make you cautious.

Keeping it from happening again

After a recovery, the most useful thing is a routine. Regular brushing, baskets that get emptied, water that gets tested and adjusted every week, and a filter that's cleaned on schedule take away most of what algae needs. Check that the timeclock is actually running the pump, and look at the pad now and then. A pump that has been off for two days is one of the quickest ways to a green pool.

If your pool has already turned, send photos. Mountain Ridge can give same-day quotes when you text or email pictures, and recovery pricing is based on what the pool actually looks like. Call (480) 382-6282 if you're in Surprise, Peoria, Waddell or Buckeye. If you'd like to keep it from happening again, weekly service is month to month with no contract.