Hello guys.
I'm in month 4 of the Aquarium cycle. Have a Blue Tang and some cleaning crew.
The stage is like you see in the pics. A lot of purple everywhere (sand, rocks, glass...)
Is this ok? Should I do something? The parameters are all ok.
For clarity, you are done cycling. Your tank is now in the process of maturing. I'd vacuum the sand and blow off the rocks during water changes to help maintain and clean up. Consider decreasing light or feeding.
traditionally cycling only refers to the period of time nitrifying bacteria takes to get established and processes available ammonia to nitrites then nitrates. This is typically a two week period tho can be shorter or a bit longer depending on methods. The purple you are showing is cyano bacteria. I would remove that via siphoning periodically to keep it under control. It's undesirable but a natural occurrence in a new tank as nutrients and bacteria seek to establish a balance.