Dublin's coast has been turned a strange brown/red colour as bathing bans remain in place across the capital.
The latest ban comes after another overflow of sewage from the Ringsend treatment plant while a number of the beaches also have seperate water quality issues.
Dollymount, Portmanrock, Sandycove, and The Forty Foot were the latest to see bathing bans which will remain in place until test results come back in about three days.
Irish Water says heavy rain led to the plant overflowing into Dublin Bay.
These are the beaches you currently can't bathe in
Portrane Beach
Portmarnock, Velvet Strand
Dollymount Strand
Merrion Strand
Sandymount Stand
Sandycove and the Forty Foot
So what is the brown/red in the water?
Despite many believing it's linked to the overflow - the colour most likely caused by an algae that thrives in the hot weather.
Pictures of Sandycove in the southside and Skerries out north show what many believe to be algal bloom - although this won't be fully confirmed until samples are tested.
Algal Bloom
Algal bloom is the increase of the algae bacteria in the water - and usually happens during the hot weather.
The increase can cause the same discolouration that's been noted on beaches across the capital today.
Is it harmful?
Different types can be and until it's been tested we won't know - early indications are that it is the harmless Noctiluca.
Dun Laoghaire-Rathdown are in the process of testing it while Fingal County Council say the phenomenon has been common in recent week.
They said: "An algae bloom (Noctiluca) was observed in Skerries, stretching from the harbour to Kelly’s Bay, this morning.
"The Marine Institute has advised this is most likely to be an Noctiluca algae bloom which has appeared frequently along the east coast in recent weeks.
"The algae is considered harmless and the event is anticipated to last between 24-48hrs.”
Is it always safe?
For bathers yes - however other types that aren't Noctiluca can be harmful and have occurred in Ireland in the past.
In 2012 a type of algal bloom killed fish, shellfish, and was linked to at least ten food poisoning cases in Galway, Mayo and Sligo.
The bloom, Karenia mikimotoi, was found on the costs from Mayo to Donegal.
It was not deemed directly harmful to swimmers - but may have had an impact on people who ate affected shellfish.
Lobster and prawn fishermen reported a lower rate of catches while oyster farms also recorded losses.
