What is causing this on the leaves? I'm not s...

High Faegrows, Your coco is too wet so your roots do not get enough oxygen. You do not have to water coco everyday. Especially in the first 2 weeks. Just stop watering this plant till the coco is totally dried out and her leaves will start to move up reaching towards the light instead of bending down like a claw. From than you can give water once in the 3 days. Just start giving around 5% water from your pot volume. And when she starts to get more thirsty (when she got bigger and need more water) then you can give around 10% water from your pot volume every other day. This also makes sure that you flush the old nutes and build up salts away. And the answer for your other concers is that this coco is still 100% usable. Coco is nothing more then dried coco fibre and can not be spoiled. You can even re use it after a grow. But I would recommend to use fresh coco every round because it is cheap and this can prevent problems during the grow. Happy growing!