Yellow Algae On Rocks

[Becks1985]

Ok cheers... Would the uv sterilizer do anything for the diatoms are will it just clear up a bit over time?.

 

[snazy]

UV sterilizer is no harm. If you have one, put it on. It needs a very slow rate to work properly so you may want it separate from your filter. But it will help with other possible types of algae and floating bacteria depending on the size of the UV.
 
However, the diatoms should clear over time. They are never permanent resident once the tank stabilizes and there are no other issues causing it, like the ones I mentioned.