need advice on adding decor to my tank.

sigh ... my tang has died ... he contracted an illness i was unable to identify .. some slimy thing all over him ... lost him within the day ..

just another question: i am not sure of the strength of my power head ( this one is just for creating current ) but the fish seem to be having porblems swimming across the stream of water.. is that ok ?

update : i add more LR to my tank .. about 6 KG .. so in total my tank should have about almost 25 - 30 KG of LR.
 
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