IMO and experience, if TSS fails , theres usually a reason...whether it be too soon of water changes, to meds killing the bacateria, to this ...I think tina that the fish store sold you way too many fish for a 10 gal and the TSS was overloaded with too much ammonia to handle and failed...again its just my opinion ...and also, you having ammonia in the tap water, keeps the ammonia up there because of the bacteria not processed yet and it keeps getting overwhelmed

you need a few water changes until that tank finishes its cycle, with spring water or something other than from your tap...once the cycle is done, there should be no problems with the bacteria handleing the ammonia in the tap, as long as you dont overstock the tank..