Dark color on pool bottom/wall - HELP!

[AnneSteph]

Can anyone tell me what this dark coloring is at the bottom and side wall of our spa?
SWG
Gunite pool w Florida Stucco Gemcoat
Color: Bone
14x42 size plus spa 8x10
Have had the same weekly maintence company since the pool was installed. They cannot definitely tell me what it is just that I should acid wash the entire pool and spa.
Have never owned a pool before….see photos
TIA

 

[Bperry]

Can anyone tell me what this dark coloring is at the bottom and side wall of our spa?
SWG
Gunite pool w Florida Stucco Gemcoat
Color: Bone
14x42 size plus spa 8x10
Have had the same weekly maintence company since the pool was installed. They cannot definitely tell me what it is just that I should acid wash the entire pool and spa.
Have never owned a pool before….see photos
TIA

Could be metal staining or algae. How are you chlorinating now? Black like that tends to be copper or algae.

Rub a trichlor puck on it and see if it lifts. If it does, it’s algae.

 

[mknauss]

Black can also be silver.
Do you use any 'mineral' packs, etc?
List the equipment you have. Post pictures of the equipment pad if you need help identifying things.