Water Change And The Affect Of Chlorine

[Greg13]

just thinking about a water change for my tank, do i need to treat the 'new' water to remove the chlorine even if it is only a small percentage of the water in the tank? i dont hink thwe small amount will hurt the fish but i thought i had better check. And do i need to heat the water to help the fish and avoid cold spots?
Greg

 

[bobbicus]

Yea ALL water has to be de-chlorinated before it enters the tank

as the more water changes you do and DON'T de-chlorinate it - the level of chlorine will rise over time!

 

[carrera]

yes, i treat the new water per bucket and put some from the hot tap in too, judging the temperature by touch to try and keep temp change as little as poss

 

[Greg13]

Thank ya!

 

[Bullrock74]

Yea ALL water has to be de-chlorinated before it enters the tank

as the more water changes you do and DON'T de-chlorinate it - the level of chlorine will rise over time!

Actually, if it's just chlorine, then it will dissipate and escape the water...some people don't use dechlorinators, they just let their tap water sit in a bucket for a day or so before adding it to their tank. But, if you have chloramine you should treat the water before putting in a tank.

 

[bobbicus]

think we would all like to have buckets of water just sat about the place!!! - but in some people's case can't be done - so to MAKE sure and for it to be done quick and effectively - dechlorinators are used

 

[Bullrock74]

think we would all like to have buckets of water just sat about the place!!! - but in some people's case can't be done - so to MAKE sure and for it to be done quick and effectively - dechlorinators are used

I use dechlorinators every time, but I just wanted to clarify the comment that chlorine levels will rise over time. That simply isn't true.

 

[Greg13]

thank ya i had heard that chlorine does leave water naturally buy tbh cba leaving it in buckets around the house! just asking for trouble
greg 8)

 

[Jules H-T]

thank ya i had heard that chlorine does leave water naturally buy tbh cba leaving it in buckets around the house! just asking for trouble
greg 8)

Depends on your own situation really. I have a 20G under a 30G which acts nicely as a resevoir for water changes for my 70.

My understanding is that dechlorinator removes dissolved oxygen from water when overdosed (and the recommended dose is bound to be sufficient for relatively highly chlorinated supplies so anyone else will be overdosing), so putting the dechlorinated water in directly may expose your fish to temporary oxygen shortages for larger water changes. I will be conducting an experiment to verify the levels we're talking about, in due course.

With this in mind, standing your water may become good policy however you treat for chlorine.

 

[sally2]

hi
Re chlorine if you draw a bucket of water and wait a day before adding -i understand that.

The warm water from the hot tap that can't wait because it'll cool down- should that be treated or is warm water ok?

 

[steelhealr]

Facts:
-just like in a swimming pool, chlorine will decrease in levels with aging and exposure to sunlight
-chloramine will NOT and is toxic to fish
-dechlorinator will NOT decrease your oxygen levels but CAN increase NH3 levels if your water quality is not good. If your tank runs acidic, ammonia can be released. If it runs alkaline, your tank will be protected as it immediately becomes ammonium.

If you want to go back to college, here is the chemistry info on how your dechlorinator works. SH

http/www.fishforums.net/index.php?showto...=0&#entry660584

 

[andywg]

My understanding is that dechlorinator removes dissolved oxygen from water when overdosed (and the recommended dose is bound to be sufficient for relatively highly chlorinated supplies so anyone else will be overdosing), so putting the dechlorinated water in directly may expose your fish to temporary oxygen shortages for larger water changes. I will be conducting an experiment to verify the levels we're talking about, in due course.

With this in mind, standing your water may become good policy however you treat for chlorine.

Most people with larger tanks dump the de-chlor in and fill up with a hose straight from the taps. I have never noticed any problems wiith oxygen shortages.

Plus, just standing water isn't that effective as the chlorine needs to be gassed out (by movement from an air pump or such) or boiled out. Boiling would also deal with chloramines (which more and more supplies have) which just leaving the water to stand would not.

 

[Jules H-T]

Most people with larger tanks dump the de-chlor in and fill up with a hose straight from the taps. I have never noticed any problems wiith oxygen shortages.

Have you specifically tested levels before and after a change? Also do you dose dechlore according to known levels of cl in your supply or do you follow the bottle? And are you in a chloraminated area or not? Purely out of interest this is.

dechlorinator will NOT decrease your oxygen levels

OK, that's the intended reaction. What does sodium thiosulphate do when it runs out of Chlorine to remove though? Apparently it pulls oxygen out of solution to make sulphate. That's from a water chemist at one of the water suppliers in the UK.

I don't know how true it is, but it makes sense to me (although my chemistry is only to A-level). I have proposed an experiment to see if it does do this, and to quantify it

http/www.fishforums.net/index.php?showtopic=138449 but there have been no takers.

Unfortunately I cannot get hold of an oxygen test until the 29th at the earliest to post results myself.

 

[rosebud280282]

I only have a small bucket about 1 gallon I think, I can't carry a bigger one because of my back. It says on my water treatment to add one capfull for every 6 gallons. Is it ok for me to add the one capfull to a small jug with some water and then add part of that to each bucket full. Hope this makes sense. Thanks

 

[andywg]

Never tested for levels, but never noticed any behavioural differences either. If the de-chlor was really going to have an effect then you would soon see my high oxygen dependant fish (large balas) at the surface trying to get some oxygen on board.

I dose to the levels stated on the bottle, though I often can't really be that bothered to work out the volume removed from the tank (especially as it requires taking the level of both sump tanks and the display) so overdose to be on the safe side. If I think I have removed 20 gallons, I will dose for about 25 to make sure.

I think there is chloramine in my water, but as the companies can change so much of the water without telling you, I would rather not risk it relying on a pirece of advice that could be out of date in seconds. That and I don't have the ability to aerate around 100 gallons of water to do my weekly water change.

I guess the reasons no one has answered your experiment is because:

1) O2 test kits aren't common (nor cheap IIRC)
2) No one has reported fish dieing of suffocation just after putting the de-chlor in and therefore any possible effects are too minor to worry about.

I have searched and searched and can find no hint about thiosulphate using up dissolved oxygen when no chlorine is present.

The only articles I can find about overdosing on ST (as one would be by putting it in tank water before replacing water with a direct hose) refer to swimming pools where they state that if you put too much ST in the tub (after overdosing chlorine) then your regular dose of chlorine will be neutralised by the residual chemical:

http/www.rhtubs.com/dichlor_vermonter.htm

That does not sound like the sort of chemical that is going to eat all your oxygen and deplete the levels for your fish if chlorine is not present.