Do Salt Water Pools Get Algae? Prevention & Treatment Guide

Tools & Supplies Needed

The Reality About Salt Pools and Algae

Yes, saltwater pools absolutely can get algae, and this is one of the most common misconceptions about salt systems. Your saltwater generator creates chlorine through electrolysis, but it's still chlorine doing the sanitizing work. If that chlorine level drops below effective ranges, algae will grow just as readily as in any traditional pool.

The confusion often stems from marketing that positions salt pools as "chemical-free" or "maintenance-free," but the truth is they still require diligent water chemistry management. Let me walk you through the key scenarios where algae problems develop and how to address each situation.

When Salt Systems Fail to Prevent Algae

Insufficient Chlorine Production

If your salt cell isn't producing enough chlorine, you'll see algae growth regardless of your salt levels. This happens when the cell output is set too low for your pool's demand, especially during hot weather or heavy bather loads. You'll want to test your free chlorine levels daily during problem periods - they should typically stay between 1-3 ppm (verify recommended range for your specific pool type and conditions).

Dirty or Scaled Salt Cell

When calcium builds up on your salt cell plates, chlorine production drops dramatically. Many pool owners don't realize their cell needs regular cleaning, typically every 3 months depending on your calcium hardness levels (consult your manufacturer's recommendations). If you're seeing low chlorine readings despite adequate salt levels, inspect your cell for white, chalky buildup.

Cyanuric Acid (CYA) Issues

This is where many salt pool owners get tripped up. If your CYA levels climb too high (typically above 80-100 ppm, though verify optimal range for your system), your chlorine becomes less effective even if readings appear normal. Salt pools using stabilized chlorine shock or certain algaecides can gradually build up CYA over time. Our complete water chemistry guide covers the relationship between CYA and chlorine effectiveness in detail.

Diagnosing Your Algae Problem

If You're Seeing Green or Yellow Algae

Start by testing your water chemistry completely - not just chlorine, but pH, alkalinity, CYA, and calcium hardness. If free chlorine is below 1 ppm, that's your primary culprit. Check your salt cell's amp draw against manufacturer specifications (always verify the correct amp rating for your specific model) to verify it's actually producing chlorine.

If Chemistry Looks Normal But Algae Persists

Your filtration system may not be keeping up, or you might have dead spots where circulation is poor. Algae can establish in areas with minimal water movement, even when chlorine levels appear adequate. I'd recommend brushing all surfaces thoroughly and running your pump longer each day.

If This is a Recurring Problem

You're likely dealing with either inadequate chlorine production for your pool's specific demands, or phosphate buildup that's feeding algae growth. Consider having your water professionally tested for phosphates, metals, and total dissolved solids.

Treatment Strategy Based on Severity

Light Algae Growth (Walls Feel Slippery)

Increase your salt cell output by 10-20% and brush the pool thoroughly. Shock with liquid chlorine if your free chlorine is below 2 ppm. Run the pump continuously until water clears, typically 24-48 hours.

Visible Green Algae

You'll need to follow the SLAM method (Shock Level and Maintain) regardless of having a salt system. The SLAM method guide provides detailed instructions, but essentially you'll maintain shock-level chlorine around the clock until algae is completely eliminated. Your salt cell alone won't generate enough chlorine for this process.

Heavy Algae Infestation

Turn your salt cell output to maximum and supplement heavily with liquid chlorine. You might need to add 2-4 gallons of liquid chlorine initially (dosage varies by pool size - verify proper amount for your specific pool volume), then maintain shock levels using our chlorine calculator for proper dosing. Brush twice daily and clean your filter frequently during this process.

Prevention Moving Forward

Once you've cleared the algae, focus on consistent chlorine production by cleaning your salt cell regularly and monitoring actual chlorine output, not just assuming the system is working. Keep CYA levels appropriate for your setup - typically 70-80 ppm for salt pools (verify optimal range for your specific system). Most importantly, test your water 2-3 times per week rather than relying solely on the salt system's automation.

Remember that salt systems are tools for chlorine generation, not magic algae prevention devices. They still require the same attention to water balance and circulation that any pool needs to stay algae-free.