Clean up your tank and put a line of Vaseline or Petroleum Jelly around the tank or in the legs of the table where the tank is.

Presto!!! no more ants on the tank!!

PS, Make sure you put some Vaseline in the cable of the heat pad because the ants will use it when they find out that you block their first route. Also if you put it in the legs of the table make sure there is no other part of the table touching the wall.

Never use any kind of poison around your herps.

Take Care