is my plant overwatered?

Those leaves look almost black, my friend.. which is usually indicative of nitrogen toxicity but I can't figure out why because you're not even giving them anything except basic root enhancers and microbes... which is another puzzlement - why no basic NPK nutes? If this is a watering issue, it could be either overwatering (the state of being constantly wet) or underwatering.... When you water, are you getting any runoff at all? If not, it's probably needing more water, not less.... Don't go by her sister - different plants will grow and need different things at different times even if they're the same strain from the same seed bank. When you water, make sure you get some runoff and then leave that runoff in the saucer/tray to see if the soil will soak it back up again... if it does, give it more water... keep giving it water until it no longer soaks up the runoff. Now, if you DO normally get runoff, then it may be overwatered. Make sure the plant actually needs water before you give it ... lift the pot up, you'll be able to tell if there's any weight in the soil or not.... if there is, wait before giving it more to drink. Good luck.... and get these ladies on some good NPK ... you're using Fox Farm so now that they're in flower, they're going to need some good Bloom nutes and Big Bloom as well as Tiger Bloom are going to be necessary - they'll need the extra PK they'll get from these.