Algae growing on pool grout

[Pamie]

We live in Southern Spain.
A few months ago we had our tiled pool re-grouted.
After a few weeks, algae started to grow on the new grout.
We dosed the pool with algaecide and then brushed all the algae off.
Within a few days, the algae had started to grow again so we shock-dosed the pool with chlorine.
Again we brushed any algae off with a wire brush.
Within a few days, it was back.
The chlorine is 10+, the ph is 7.2, and we have used a lot of anti-algae.
Not sure what to do next, any suggestions would be appreciated.

 

[ajw22]

Welcome to TFP.

Pools need to be brushed one or twice a week as part of normal maintenance. Are you doing that?

How do you chlorinate your pool?

What test kit are you using?

What ingredients are in the Algaecide you are using?

What is your CYA level?

 

[Pamie]

Welcome to TFP.

Pools need to be brushed one or twice a week as part of normal maintenance. Are you doing that?

How do you chlorinate your pool?

What test kit are you using?

What ingredients are in the Algaecide you are using?

What is your CYA level?

Thanks for your reply.
Brushing - I do it around once a week.
Chlorination: for regular use: Slow-release granules . . . for Shock: Shock granules.
Test kit: Aqua Chek strips (not as precise as drops I know, but a lot easier).
Agecide ingredients: No idea, we use Aquapool Algecida Concentrado liquid.
CYA Level: Around 300 at the moment; usually much low.

 

[ajw22]

CYA 300 is a problem if that is accurate. You would need a FC of over 30 to prevent algae with that CYA level.

You can’t measure your FC accurately with those test strips. Especially high FC you need with high CYA.

You need to lower your CYA by draining the pool and stop using granules that add CYA.

I suggest you read …

The Free Chlorine and Cyanuric Acid Relationship

Managing your cyanuric acid and Free Chlorine levels is key to stabilizing your pool. Learn how these two items affect each other.

www.troublefreepool.com

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