I have 2 sliders. I think they are of the same sex. Lately they are acting very hyper. The are constantly banging their tank and swimming like they want to get out. I take them outside and let them roam on the grass and lately they go straight to the dirt and start digging a hole. When I put them back in the tank the coninue with the hyper behavior and now I see that the tank water is turning whitish like they are secreteing something. Any advise would be appreciated. I have gotten to where I have to cover the tank to get them to calm down!