your irresponsible. you have sick toads to contend with but still go out and purchase another !!!. there is something going terribly wrong here either by having a poorly stocked petshop or your husbandry needs addressing i.e. The old tank I had to clean my self, the water got really gross and it stank to high heavens.. WHY?
pics of setup, water used: tap, purified etc and YOUR full husbandry regime would be most appreciated here. i personally think you just can't provide for their needs reading between the lines from all your posts.