White algae.?

[OoooDRAGONoooo]

Hi has anyone had a creamy white substance growing on their live rock?it looks like pieces of dead skin,it doesn't stick out more than two to 3 mm but it is spreading.its almost looks like small tufts of cotton wool.crabs, lawnmower blenny and snails ignore it.all parameters are good. Tank 6 months old.could it be just another phase of maturing tank? Ty

[alexander_ktn]

Without a good picture it's hard to say but my guess would be some bacterial mat that developed either due to something dying on the live rock or too little flow in those areas (or both).