Dechlorinators

Ya its kinda bad. One day the fish might get sick and all die because of the added chemicals. From now on I would add some of it. Another bad thing is that the chemicals in the tap water will go into the filter, and kill all the good bacteria.

just because you cant see it, does not mean damage is being done.
Treat your water each time, the whole volume not just what you changed and your bacteria will thank you for it.

if people use primes method of dosing in a smaller tank its likely that you would do like I do I add enough to treat my entire tank every time I change water though I am changing 30 or 40 percent at a time. I have not had a problem with chliorine or ammonia since using prime and big water changes with my plants and fish.

To my knowledge Chloramines are not used in Canada.

We only have chlorine in Montreal. Depending on where the water comes from where you live. Riviere des prairies or Lac St. Louis you will have either a little less RDP or a little more LSL. Either way though any old regular dechlorinator will do the job fine. In the case of smaller water changes you may not need to use it at all.

There have been many times that I have forgotten to put it in and I'm pulling water out to crappy Lac St. Louis or Pooey Louie as we use to call it as kids.

If Chloramine, I would treat it for sure. IF chlorine there is some variance in my thinking.
It largely depends on the amount of chlorine your water company uses. Fish and bacteria can both survive small amounts short term, furthermore if you have a heavily planted tank in good health, the bio-filter isn't doing a lot to begin with. Chlorine will dissipate in less than 24 hours, and since you are dilluting it to begin with, we are talking about trace amounts going into the tank.
This isn't something I would do with my tanks, but hesitate to argue that it will hurt much if it is done. If your water supplier is using heavy amounts of chlorine the danger is greater, and I prefer to estabilish a routine that won't cause me trouble when The water company changes things.

I never use dechlorinator, but I do age my water before it goes into the tanks.

Either way the absolute safest route is to use prime or an equivalent dechlorinator/ dechloriminator, and not take a risk.
dave

To help me decide what I was treating for, I used a Aquarium Pharmaceuticals kit that included tests for chlorine and ammonia. As it happened, the tests determine if your water company uses chlorine or chloramine. It turned out my water company uses chlorine. At any rate, if I don't filter my water before I water my house plants, the leaves will turn yellow. You can imagine what it would do to aquatic plants, not to mention the fish, if I did not use a conditioner.

Your best bet would be to test the water in the tank since you have not used a conditioner for awhile. I bet your tests come up positive, as whatever may have already been in the tank is probably not enough to tackle new water from the change you are doing. Remember, the water in the tank is degraded and that's why you are doing the change in the first place. The test will stop the questions in your mind, but I would not recommend relying on the effectiveness of the conditioner that remains in the tank from the previous water change.

Chloramines ARE used in some places in Canada.

Ottawa for example.

Chloramine is actually worse for a fish than chlorine because chloramine is ammonia and chlorine bonded together!