If you set your tap water in a pitcher or something open to air the chlorine will evaporate off in 24 hrs.

The only real with tap water would be mainly PH. Most city tap water is a little high in PH intentionally because it's better for the pipes and equipment. That is unless your water is real hard or real salty, but that's uncommon and unlikely.

Mine takes 1/2 teaspoon of vinegar per gallon to get to a good PH.

I'm with Stinky, I think you've probably way over fed them. A good flush with water at the right PH and let them sit a few days and they will probably perk up if they aren't too far gone.

Then maybe feed em with a weak solution.