Algae?

[DJWildWilly]

Tank is 3 months old, have this long flat rock about 12 inches below water line. It has a nice layer of green algae and some pink coraline spots appearing, but the very dark spots( black?) are new and I do not know what they are, or if good or bad.
Can anyone one offer advice on the dark spots?

tank parameters:
Ammonia, nitrites, and phosphates =0
Nitrates= 10
PH = 8.0
Salinity = 1.025
Calcium = 440

 

[elorablue]

is it hard or fuzzy or stringy?

 

[DJWildWilly]

is it hard or fuzzy or stringy?

Do s not blow off with a vaster, no apparent fuz or hair… just like slightly raised ink dot ( looks a lot like an oil droplet in water?

 

[elorablue]

Not sure really. I would guess, and it’s just a guess, that it’s just a normal aging of the rock. All sorts of colours show up during the ageing process.
wish I could help more.

 

[DJWildWilly]

Not sure really. I would guess, and it’s just a guess, that it’s just a normal aging of the rock. All sorts of colours show up during the ageing process.
wish I could help more.

No, thanks for trying elorablue.