red staining on concrete

countrywoman

Not sure if this is on the right forum? Does anyone know what the red staining that appears on concrete is? Sometimes it can be seen on houses.
Any ideas on how to get rid? Its all over kerbs along my driveway

Thanks

LurkerNo1

You can power hose it off or dilute bleach and spray it on with a knapsack sprayer and use a regular hose a day or two later to take it off or just let the rain do it. Both of these worked for me.
Is it some type of lichen i wonder?

countrywoman

Thanks Lurker.
I hadn't thought of bleach, would it do Any damage to nearby plants I wonder?

secman

Its a kind of algae, I usually use the MossGo and in the past it has got rid of it.

Secman

countrywoman

Sec man, I actually have a 5litre bottle of mosgo in the garage!

rmurph1

It's a red algae that lives in pourous stone, very common in Ireland due to the fact that it thrives in wet climates espically with salty air.
You can kill it with a hydrochloric acid mix but that doesn't stop it coming back, NP Liquid Glass Systems has a product that kills it and prevents it for coming back as they apply the Liquid Glass to your stone walls and it binds to the surface killing the algae and stopping it from growing back, they're on Facebook

Glebee

I usually use MossGo each year in late spring / early summer to get rid of it on walls and roof tiles that are lying in a sheltered position.

I notice that MossGo have a newish product out specifically for that red and green growth. Dont know if its much different than the standard Mossgo.