Black spot on bottom of pebble tec pool

[Dennis88]

Hi there,

My in ground Pebble Tec pool is 15 years old. A black spot has appeared at the bottom of the pool. I tried scrubbing and applying chlorine to the spot but nothing has changed so I don't think it is black algae but not really sure ?

I have attached a pictures and hopefully this will be of some help!

Thank you so much,
Dennis

 

[needsajet]

Welcome to TFP! Good to have you here

Try brushing it, then put a trichlor puck on it for 5 minutes. Then brush again, and put the puck over it for another 5 minutes. Then take the puck out of the pool. Check it in a couple hours and see if the dark spot has lightened up.

Don't leave a puck on it any longer or it may lighten the plaster.