How To Remove Chlorine and Chloramine and Why?
Chlorine is added to new water at the “water company” so they don’t send their municipality a disease. Stuff like toxoplasmosis, cryptosporidia etc. Heck, just germs. Chlorine kills that stuff and just happens to kill fish.
You can make your own dechlorinator with instructions at drjohnson.com
Or you can just buy dechlorinator
You should use dechlorinator with every water change over 10% but if you’re always trickling water (10% per DAY) you don’t have to worry about dechlorinating either.
Chloramine dissociates into neutralize chlorine and free ammonia, which occurs in small amounts as a by-product and is easy for any ‘cycled’ system to utilize and thus remove from the water column.
Sodium thiosulfate granules are economical in ponds, some people just scatter the recommended amount in the pond with water changes. Others can make a stock solution with water and use that. Instruction on how to do that are at Drjohnson.com use the search engine there.
There are numerous dechlorinator solutions premade and easy to get and use. I use this one in small tanks (under 300 gallons) because frankly I'm too lazy to mess with all the measurements and mixing of my own solutions.
This is API's "economy" size dechlorinator, I bought a bottle of this when I set up my fish room because I needed a LOT of dechlor and it's premeasured and easy.