White/grey goo on wood. New tank.

It looks like the mould that normally grows on new pieces of driftwood introduced to the aquarium. There is nothing to worry about, as it is harmless, if not unsightly.

You can try boiling the piece of wood and/or scrubbing it, but the mould will likely come back. It will disappear on its own after a few weeks, however.

Awesome! I boiled it once beforehand. I have removed from tank and am boiling again. Good to know it is harmless. I am buying some trumpet snails and SAE's tomorrow for the first addition of creatures to start the cycling (and perhaps control any future algal outbreaks). Any comments on this?

Have you looked into fishless cycling? It is more commonly used than trying to use fish to cycle an aquarium, as it does not cause undue stress.

I have not. But will do. There are no nitrates or ammonia in the tank. Without fish, how else can these be added for the health of the plants?

Ammonia can be easily added to an aquarium to start the fishless cycle. Pure ammonia can be purchased at hardware stores, as it is commonly used as a cleaner. You want a bottle of ammonia that does not contain any fragrances, detergents, etc.

Easiest way is to put a piece of raw deli shrimp in the tank and wait