Dechlorinating Water for Pond

I have a 3000 gallon pond that I normally top off using my well water. The
house is on city water, the well pump quit after 17 years and it is getting
replaced. I need to top off the pond with about 200 gallons of water. Anyone
else here ever buy a applicator for fertilizer that goes on the end of hose
, mix the appropriate amount of water and dechlorinater in the jug and top
off there pond? I am doing it as I write this, I actually put twice the
required amount of dechlorinator in the jug and put enough for 2500 gallons
at the intake of the pump to spread it around. How do other people deal with
this when you use city water?