Its Hard to say what needed for sure. but common things like topping the tank off, water testing feeding, general cleaning should be done
Feeding daily and tank cleaning once weekly usually works fine.
Testing water should be done monthly on established tanks to ensure everything is doing well water quality wise
Observe fish every time they eat to ensure proper health.
The pic that your showed of your rock looks bad. I posted a comment in another thread about it and this thread answers my question lol.
What i would do, this may sound bad but take the rock out, soak in non salted filtered water (RO/DI) and kill all the algae off. Then let it re cure in a different container. After rock is cured, add back to tank and make sure the problem dose not persist. Possible causes are usually pointed towards your water. Levels that the tank is at and the source of the water. RO/DI should be used to ensure the best water possible with the lowest amount of any trace elements in it.
Post your water params and we can tell you more--test nitrate, phosphate and silicate if you can.
Also how long are your lights on a day??
