my pot is full to the top with soil.. should i let the soil dry, remove the top lair and put sand down? can i buy perlite at home depot/lowes?
Yes. Be very careful when removing the top layer as not to disturb any roots. Yes. Atleast around my area perlite can be found at home depot, lowes, or even walmart. Your gonna want a solid 1" layer on the top to prevent them from tunneling down into it.
Have you checked the bottoms of your leaves with a scope or magnifying glass? Spider mites are a pain and can destroy a room full of plants in a short amount of time. The main things you would be looking for are small black spots (waste from mites or other), small greyish/white/brown "spider looking" things (hence the name spider mite)
Slugs could be the culprit if its possible they could reach the grow room. Also caterpillars. If they are larger bites then it could possibly be a mouse/mice. I've had them eat leaves, whittle away at the mainstem, and even chop it down similar to a beaver and haul the seedling/young vegging plant away. Mice love cannabis. They will find and eat any seed, not to mention make bedding out of the seed hulls.