Water, clarity and algae
Foam on pool water
Foam rarely means the water is dangerous. It means something has entered the pool that makes the water froth wherever it is agitated.
Foam appears where water is churned: around return jets, spillways, waterfalls and around swimmers. The usual cause is something that lowers the surface tension of the water — sunscreen and body lotion, hair products, detergent left in swimwear from the washing machine, or an algaecide added in larger amounts than the label suggests. Very soft water can also foam more readily.
Water guides explain what a reading or a symptom means and the order in which to correct it.
Anti-foam products clear the bubbles quickly, but the foam returns if its source stays in the water. A lasting fix means oxidising the organic residue, filtering it out, and changing whatever is bringing it in.
The short version
Swimmer residue is the common cause
Lotions, cosmetics and detergent in swimwear build up quickly after busy weekends.
Some algaecides foam
Certain types, especially in larger doses, foam as soon as the water is agitated.
Anti-foam is temporary
It breaks the bubbles but leaves the cause in the water.
Clearing foam properly
Oxidising the residue
A shock dose, with pH in range first, breaks down the organic film that holds bubbles together.
Cleaning the filter
Oils and lotions coat sand and cartridges; backwashing or degreasing the filter removes what it has trapped.
Reviewing products
Switching to a non-foaming algaecide, or dosing it correctly, stops chemical foam returning.
Questions that find the source
Was algaecide added recently?
Note the product and how much was used against the label dose.
Was there a party or heavy use?
More swimmers bring more lotion, sunscreen and cosmetics.
Are swimmers showering first?
A quick rinse before swimming removes much of the residue.
Common questions
Is foam on the pool harmful?
Usually not, but it signals an organic load or an overdose that should be dealt with before the water dulls or clouds.
Why does foam appear only at the spillway?
Spillways and water features agitate the water most, so they show foam first.
Can a new pool foam?
Occasionally, from start-up chemicals or very soft fill water. Balancing the water usually stops it.
Related pool care guides
- Looking after a pool after heavy rainAnother water problem with a related cause.
- Cleaning a pool after a sandstormAnother water problem with a related cause.
- Test strips or a liquid test kitA related choice about how the pool is looked after.
- Stabilised or unstabilised chlorineA related choice about how the pool is looked after.
This guide sits under pool water treatment. Browse all pool care guides. We look after pools at homes and commercial properties across Dubai.
Ask about your pool
A clear photograph and your latest test reading are usually enough for a useful first answer.
Phone
+971 56 181 0106Talk through what the pool is doing and book a time for us to see it.
WhatsApp
Send a messageThe easiest way to send photographs of the pool and plant room.
Next step
Foam keeps appearing?
Tell us what has been added to the pool recently and send a short video of the foam. We will help identify the source.