The black string retractable, spring-loaded lamp hangers are known for breaking at the plastic threaded hooks. China said they would fix the problem a few years ago. lol Search around and you'll see quite a few lamps and hoods crash landing on girls. However, those chains are proven and legit.

Your plants look good. Slight yellowing/light burn on the tips is a good sign you're delivering the maximum nutrients to the plant. The spots on the one leaf, could be a number of things. Usually when you see it low it's chemical burns from nutrient water. Sometimes it's VPD(vapor pressure deficit), you'll see the spots eventually lose all chlorophyll if not corrected. Sometimes w/ tight internodal strains when the fingers overlap you'll see them sweat where the two foliage surfaces meet, typically in hot systems. All that mumbojumbo blah blah...if it's one or two fingers or a couple of fan leafs at the bottom it's not worth trying to correct. If you think it's bugs you can use neem oil to mess up their daily life. Sticky traps at the base of the plant.

cheers