Water changing question

[TCool]

I've been using an aqueon water changer (like the python) and I've read that you should put in enough dechlor for the entire size of the tank when filling it back up. I've also read that you should only put in enough for the amount of water you are adding.

My thinking is this:
Putting in enough for the entire size of the tank is correct because otherwise it is going to be diluted too much by the water that is already in there. But, it could also be wrong because the water in there is already dechlorinated, so it'd be adding extra dechlor that doesn't need to be in there.

Which way is correct? And, for the record, I've been putting in enough for the entire size of my tank. I've also been thinking of removing my filter (it is internal power filter) for a few minutes while filling it back up, or does that dechlor act instantly and I don't have anything to worry about there?

 

[neilanh]

I always put in enough for the whole tank. Overdosing dechlor is not a huge concern (not that you should dump a whole bottle in there or anything)

 

[mgamer20o0]

if you are treating water in a bucket you can just treat for that water. if you are just filling a tank up its best to fill for the whole water volume. i mean prime is so cheap why risk it.

no need to remove the filter. what i do is add prime to the tank then fill it up. been working for me for years.

 

[BigJim]

I always add extra dechlorinator and I've never had an issue.

+1 on not removing the filter.

 

[CA_BroncoFan]

I always add extra dechlorinator and I've never had an issue.

+1 on not removing the filter.

Completely aggree. I always add a touch more just in case

 

[Phazeshyft]

+1 for treat whole tank and my reasoning is this.
1) the Dechlor works pretty quick
2) the reagent in the dechlor is not toxic to fish and carbon will pull any extra out.
3) I dont run my filters while i change water so by the time its full the dechlor has had time to work.
4) I hate having to "guess" how much water I pulled out, I havent really taken measurements on my tank to know, "this much 10 or 20 gallons"

 

[neilanh]

I don't agree with not removing the filter during your PWCs. I have canisters, so I don't actually remove them, but I do turn them off. The idea is to keep the untreated water from contacting the bacteria that are growing in the filter media - as the chlorine in the water will kill them. As you're filling your tank, even adding dechlor, you're adding a lot of water (esp if it's a big tank) so it takes a little time for the dechlor to mix with all the water. I try to protect my filter media from having the chance to be touched by untreated water.

 

[TCool]

Ok, I think I'll go the safe route and remove my filter. It is an internal filter, so I was worried that the chlorine would be contacting the filter before the dechlor worked. I'd imagine just turning it off really would have no effect since it is sitting in the tank, the new water is going to be coming in contact with it regardless of whether it is running or not.

A little off topic, but I must say internal filters are so much more of a pain in the butt. Definitely worth it tho(imo) for the quietness and ability to protect my walls from my crazy fish.