Algae growth is an Arizona homeowner's most common pool problem — and it can happen surprisingly fast. A pool can go from clear to pea-soup green in 48–72 hours when chlorine runs out, circulation stops, or a dust storm drops organic material into the water. Heat accelerates algae growth and UV accelerates chlorine loss, creating a perfect storm.
Pro Tip
A pool that turns green after a vacation almost always had a chemistry problem before you left. Test and balance before any extended absence.
Calculate the correct dose of calcium hypochlorite shock based on your pool volume and algae severity. For severe blooms, triple-shock is often necessary. Add shock at dusk — UV breaks it down in direct sunlight. Run the pump continuously for 24 hours after shocking.
Pro Tip
Add shock in multiple smaller doses at 12-hour intervals rather than one massive dose. It's more effective and gentler on pool surfaces.
As algae dies, it settles on the pool floor as dead gray matter. Vacuum directly to waste (bypassing the filter if possible) to remove it without clogging your filter. For severe pools, this step may need to be repeated multiple times as water clears progressively.
Once the pool clears, test and rebalance all chemistry parameters. Then identify why it happened: insufficient chlorine, poor circulation, clogged filter, or lack of service. Address the root cause or your pool will green again quickly.
Get a free estimate from Mirage Waterscape — Scottsdale's trusted pool care specialists.