Need urgent help with sick toads

Question
I woke up yesterday to my one of my three toads laying on his back with his
legs outstretched, and quickly noticed one of my other toads having what
appeared to be a seizure with his legs outstretched and his stomach vibrating.  
I put him in a separate container with a little bit of water in the bottom
thinking perhaps that he was dehydrated, and he seemed to get better.  A
little later he had another seizure and died.  Just now I noticed that the third
toad is jumping around the terrarium frantically and flopping onto his back...  
I am really disturbed by this.  I feel absolutely awful and helpless.  I would
think maybe it was something like a calcium deficiency but for three animals
to have an acute condition like this simultaneously seems more like an
infection of some sort of maybe even poisoning.  I know that frogs and toads
are very sensitive to chemicals though, so I use none near the terrarium.    
There are other amphibians in the tank but they are all treefrogs; no toads.
They seem fine for now but that could change at any time.  If there is a way I
can prevent these animals from dying I would really love to do that.
Thank you in advance!

Answer
OK, honestly, this sounds like what is known as Toxing out.  This occurs when the water used the terrarium is not changed daily as it should be.  I am not saying this is what has happened but maybe what has occurred is that with so many frogs in the enclosure the ureas and ammonias have built up more quickly than normal.  The cure is to exactly what you did and place them in low level of clean dechlorinated water.  It also maybe that the water company in your area has increased ammonia levels which is why I only use bottled or store bought water with my amphibians.  While more costly it definitely prevents what you have described.  I am really leaning towards the toxing out diagnosis as the symptoms match exactly.  Barring taking it to a vet this is the best I can tell you.  I am sorry for your loss and do hope that this helps the remaining frogs and toads to get better.  Please let me know if I can assist further.