What up with plants?

[seangee]

Personally I find it easier to pinpoint problems by changing one thing at a time. That way I know which one made the difference

 

[seangee]

It looks like algae growing on the leaves.

If it is algae (and there is a good chance) it will wipe off. You can use your fingers or a kitchen sponge / scourer thingy - just make sure its clean and not impregnated with any chemicals or detergents.