Dechlorinator after or before pouring water? What do you do?

[Errk25]

I have five smaller tanks, 29 and 10 gallon, and use five gallon buckets. I add dechlorinator to buckets before hand. Have a 150 gallon tote pond outdoors and just top off with buckets too. After some recent back problems I’m thinking about using a python though. Never heard of anyone having problems with adding full dose for the whole tank when using python. 

[Paul]

I use a Python to do water changes straight from the tap. Sometimes I add the Prime (full dose for each tank) before, sometimes during and occasionally after filling the tanks with no ill effects. I think the idea is to just get it in the water asap. 

[Leo2o915]

On 9/8/2020 at 8:35 PM, HenryC said:

I always find conflicting inputs on this one, so I would love to ask you guys, what do you do when you water chage:

Do you pre-treat the water with dechlorinator before placing it in the tank...
or
Do you dose dechlorinator straight to the aquarium, then pour new water in?

Some will tell you you will kill your fish and benefical bacteria the moment you pour new water in the tank, as the dechlorinator takes some time to neutralize it, others have told me they been doing it for ages with zero issues, they claim the chlorine concentration is so low that I won't do any harm (they argue that if the chlorine in tap water was so potent as to instantly kill your cycle and fish, we would be using tap water to disinfect wounds).

I personally pre-treat before pouring new water in cause I fear for my fish safety. but as I get bigger and bigger aquariums, it seems that pouring dechlorinator to the aquarium then using the hose to fill it up is going to be miles ahead in terms of convenience, but I do not wanna shock my fish.

What do you do?

I used to during but I pre treat my water in a 32 gallon bucket the night before with a water pump and add the water treatment a hour before 

[Leo2o915]

On 9/8/2020 at 8:35 PM, HenryC said:

I always find conflicting inputs on this one, so I would love to ask you guys, what do you do when you water chage:

Do you pre-treat the water with dechlorinator before placing it in the tank...
or
Do you dose dechlorinator straight to the aquarium, then pour new water in?

Some will tell you you will kill your fish and benefical bacteria the moment you pour new water in the tank, as the dechlorinator takes some time to neutralize it, others have told me they been doing it for ages with zero issues, they claim the chlorine concentration is so low that I won't do any harm (they argue that if the chlorine in tap water was so potent as to instantly kill your cycle and fish, we would be using tap water to disinfect wounds).

I personally pre-treat before pouring new water in cause I fear for my fish safety. but as I get bigger and bigger aquariums, it seems that pouring dechlorinator to the aquarium then using the hose to fill it up is going to be miles ahead in terms of convenience, but I do not wanna shock my fish.

What do you do?

Go to Lowes or Home Depot and buy 2 32 gallon totes/trash bins and pre treat that way and add with water pump 

[Leo2o915]

On 9/8/2020 at 9:33 PM, StephenP2003 said:

I use the python system straight from the tap. I usually do 50% water changes, and I add a full tank's worth of prime right before or during the fill-up. I've never had any problems. My tap water, according to my city's quality report, has as much as 2.2 ppm chloramines.

I wanted ur opinion on something bro I’ve seen people out where it snows and they add a lot of salt and chloramine more during the winter don’t you guys worry about them double dosing they chloramine?  That’s why I started pre treating even though it doesn’t snow over here in the valley just we already get tap water with nitrates out of the tap here in Cali 

[StephenP2003]

2 hours ago, Leo2o915 said:

I wanted ur opinion on something bro I’ve seen people out where it snows and they add a lot of salt and chloramine more during the winter don’t you guys worry about them double dosing they chloramine?  That’s why I started pre treating even though it doesn’t snow over here in the valley just we already get tap water with nitrates out of the tap here in Cali 

It doesn't snow here (well, one day every 10 years or so), but I didn't know that was a thing (adding more chloramine and salt in the winter). Water quality/content seems to stay within a narrow and safe range. The TDS is almost all attributed to Calcium Carbonate -- my KH is about 120ppm out of the tap. Strip tests show around 1.0ppm chlorine in my tap water; since I have chloramine, that likely means I also have about 0.2ppm of ammonia (based on my Googling that chlorine and ammonia are usually mixed 5:1 to make chloramine, but my water tests never detect it).

My city's annual water quality report says the range of chlorine detected ranges from 0.63 ppm to 2.2 ppm at its worst (I think they pump regular chlorine through every so often to clean the pipes).  Since I do 50% water changes and dose a full tank's worth of prime, I assume I would be covered by a small spike in chlorine from the tap. I also assume, maybe incorrectly, that dechlorinator dosages account for chlorine levels a little higher than mine (Google says as much as 4ppm is safe to drink, and 2ppm is not uncommon). 

All that said, my decision to dose prime while filling instead of pretreating certainly isn't based on any of my own scientific knowledge. I saw lots of youtubers doing it that way, so I started doing it too. If something catastrophic ever happens related to a water change, I'm sure I'll revisit this method.

 

Edited September 10, 2020 by StephenP2003

[Alison]

I do not use a python at this point but I also dump the prime into my tank and then  add the water. So far it has worked well for me and I haven't seen any signs of distress in my fish. Other than them being unhappy my hand is in their tank that is.

[Ben Ellison]

I would like to see a python type device that has a chamber for Prime to be added at a metered rate. I am looking into getting a chlorine block filter and automatic thermo valve that u can set and a large tank to age water in.

[Leo2o915]

3 hours ago, StephenP2003 said:

It doesn't snow here (well, one day every 10 years or so), but I didn't know that was a thing (adding more chloramine and salt in the winter). Water quality/content seems to stay within a narrow and safe range. The TDS is almost all attributed to Calcium Carbonate -- my KH is about 120ppm out of the tap. Strip tests show around 1.0ppm chlorine in my tap water; since I have chloramine, that likely means I also have about 0.2ppm of ammonia (based on my Googling that chlorine and ammonia are usually mixed 5:1 to make chloramine, but my water tests never detect it).

My city's annual water quality report says the range of chlorine detected ranges from 0.63 ppm to 2.2 ppm at its worst (I think they pump regular chlorine through every so often to clean the pipes).  Since I do 50% water changes and dose a full tank's worth of prime, I assume I would be covered by a small spike in chlorine from the tap. I also assume, maybe incorrectly, that dechlorinator dosages account for chlorine levels a little higher than mine (Google says as much as 4ppm is safe to drink, and 2ppm is not uncommon). 

All that said, my decision to dose prime while filling instead of pretreating certainly isn't based on any of my own scientific knowledge. I saw lots of youtubers doing it that way, so I started doing it too. If something catastrophic ever happens related to a water change, I'm sure I'll revisit this method.

 

Hmm I’ve filled it straight from the tap too but one of the YouTube channels I follow lost almost his whole tank when they doubled the chloramine so it made me take the safe way just to be cautious 

[Ryan W]

In my experience (about 8-9 years), with my tap water, it doesn’t matter when I implement dechlorinator. Sometimes I flat out forget about it all together. However, not all water is the same and some areas of the country you can literally smell the chlorine while the tap is running. In cases like that, I would implement dechlorinator before EVER entering your tank and may even consider adding the routine of leaving my change-water sit overnight with an air stone to help off-gas the chlorine instead of solely relying on a chemical dechlorinator.

But, with tap water within “regular” chlorine levels, it hasn’t seemed to matter.