[Blue Ridge Reef]

The white fungus on driftwood is usually just biofilm growing from the leeching sugars. I'd bet your shrimp are appreciating it even if there is more than they can consume. As for the sulphur smell, whenever you have a deep substrate bed there is going to be anaerobic bacteria and you'll eventually have that. For partial water changes I like the small size Python brand siphon for nano tanks of this size. That looks like standard aquarium gravel so you should be able to use a small siphon like that without uprooting plants (as can be the case with really light soils). I'm an advocate for a series of small partial water changes rather than one large one, particularly in a shrimp tank. And I agree with Cinnamonamon that stand and canopy look fantastic!