Yes, I am spraying them every day. The plants actually seem to have perked up with the extra ferts. I was using a very weak solution up until last night. I've only had the plants in there for 13 days now and they were all in submersed growth form when they arrived, so I think they're just adjusting to emersed life.
I agree that the substrate is too deep, but I don't want to disturb the plants right now, since they're still putting roots down. I'm afraid that if I uproot them all to take out some sand, it will kill them.