The links Crystal gave you have great info. I've raised both frogs & toads from tads. One thing I've always done is add an airstone to the tank to help oxygenate the water. And if the pump is to strong, just poke a few pin holes into the tube so the force isn't so strong. Now if some of the tads do die, leave the bodies in there, the others will eat them which is a good source of protein for them. Post pics so we can see the transformation, it's an amazing thing to witness.