Water Change And The Affect Of Chlorine

[@ombomb]

I have never tested the levels before / after a change either, but it's clear from the reaction of the plants that te water is still saturated with oxygen as they pearl like mad for a full day, then calm down to their normal level.

 

[Jules H-T]

Stealhealr, what is the basis for your "fact" that dechlorinator doesn't reduce oxygen content? The absence you being aware of any evidence that is does, is not going to be good enough for me. (BTW stealhealr, since I joined you're the guy I've always looked up to, read your theads with great interest and respect, ahead of no-one: so please don't take this as an attack).

The more I read, the more I'm thinking it does. Anyway, I've found the following thread really very interesting:

http/www.eng-tips.com/viewthread.cfm?qid=142362&page=4

I note that post 4 mentions the scavenging of oxygen, although it doesn't quantify it.

I don't suppose that you might live in a chloraminated area by any chance? That would be very handy.

I will post the results for my non chloraminated area, and I swear they will be honest. Let's have a look? We can google links all day, but if we take the pepsi challenge, then we can start talking facts with some authority. I don't care if oxygen is reduced, or even if it is, whether it is to a level where our fish might suffer, but sometimes honestly I wonder whether the fishkeeping establishment actually thinks for itself or follows accepted wisdom.

I'd very much appreciate Saedcantas' view on this, as they seem like a very knowledgable person on this sort of thing.

It also mentions that thiosulphate is "not very toxic" to aquatic species, which is very interesting to me as I've been asking about that and drawn pretty much complete blanks, with a few notable exceptions.

It also says "Sodium thiosulfate may react slowly with chlorine under some conditions, and requires more time for dechlorination than most dechlorination chemicals"

Whether that is a bit of a worry for the "turn on the tap and add the dechlore" peeps, I could not say.

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What I'd like to say at this point is that I know I've rubbed the backs of senior members and mods, up the wrong way with my relentless pushing of certain things. For me, questioning established wisdom is part of the way I look at things and make my living, and consequently it filters through to my fishkeeping.

Hopefully it is accepted as productive, if irritating. Either that, or I'll get banned! Hopefully the former.

 

[bobbicus]

just a few questions..........

i thought that a de-chlorinator (although there are different brands) not only de-chlorinates (clorine and chloramine) but also makes the hard metals in water safe for aquatic life - which if the water is not treated this can affect the carbonate and general hardness?

also by taking hot tap water - some water supplys that have hot water - contains copper piping and this can be transferred into the water?

also boiling from a kettle there sometimes (in used kettles) a build up of calcium carbonate and this can affect the water hardness too - needing a de-chlorinator which neutralises this?

i think if de-chlorinators removed oxygen from the water that aquatic life and the bacteria that is needed in an aquatic environment - specifcally need to sustain/maintain their existence - then what is the point of producing a de-chlorinator?

 

[Jules H-T]

i thought that a de-chlorinator (although there are different brands) not only de-chlorinates (clorine and chloramine) but also makes the hard metals in water safe for aquatic life - which if the water is not treated this can affect the carbonate and general hardness?

Heavy metals, not hard ones. The kh and gh are unaffected by the heavy metal content of the water as far as I know, although the toxicity of those heavy metals is dependant on these factors, which is different. Search for dechlorinator and my username and you'll see a thread started by Moody with loads more info on this subject.

also by taking hot tap water - some water supplys that have hot water - contains copper piping and this can be transferred into the water?

Too right. I'd never take from a hot water supply personally.

also boiling from a kettle there sometimes (in used kettles) a build up of calcium carbonate and this can affect the water hardness too - needing a de-chlorinator which neutralises this?

There may well be a build up of calcium based compounds in your kettle, but I wasn't aware that dechlorinators changed that. Are you suggesting that dechlorinator is a water softener?

i think if de-chlorinators removed oxygen from the water that aquatic life and the bacteria that is needed in an aquatic environment - specifcally need to sustain/maintain their existence - then what is the point of producing a de-chlorinator?

Yeah but you're randomly speculating. With beer and water in abundance I could ask what the point of coca cola is, but they still make it, it will still rot away a tooth overnight, and millions of people still drink it.

 

[steelhealr]

Jules..hey...no problem and thanks for the initial comment. Being a biochem major in college, I have to turn it around on you. Looking at the equations given in the link on the other page, tell me where you see oxygen consumed in the reactions? To reduce the oxygen level in the water, oxygen must be:

1) either consumed in a chemical reaction, or
2) driven off by heat
3) metabolized by life and not replaced.

Unless I am missing something in my chemistry, I don't see where oxygen is used in the reactions between chlorine or chloramine and any of the sulfur containing thiosulfates.

Besides, and not being able to come up with numbers, the agitation at the water surface and diffusion would far away overwhelm any loss of oxygen, even if it was consumed, by as small as a reaction as this. SH

 

[WayneVT08]

So you do need to do a de-chlorine test before each water change? Or what?

 

[steelhealr]

NOOOOOOOOO. Just dechlorinate. The amount of dechlorinator in the recommended amount of dosing is WAY above the amount of chlorine in your tank. Dechlorination is almost instanteous.

I recharge my Purigen media by placing it in a small mixture of Chlorox and water, 1: 10. Obviously, it reeks of chlorine. After rinsing, I add a small amout of dechlorinator and the smell of Chlorox disappears immediately. SH

 

[Jules H-T]

That's because you're missing my point stealhealr- the thiosulphate has an affinity for oxygen as well as for chlorine. So your equations involving the chlorine side of things are only showing part of the picture. This has come from a water chemist, and seems to be backed up by engineers. It's fine if you doubt it, and I do intend to find out for sure.

However, it is dangerous for you to say that dechlorinator doesn't remove oxygen, for a fact (and as the scientist that you obviously are, it is quite surprising that you did).

In the absence of a high chlorine count, you may temporarily reduce oxygen content, although to what level I do not know. Perhaps the reason this isn't an issue is that the level isn't significant.

Also, no doubt like you say any oxygen would soon be replaced, but there is the meantime to consider. Where this may become important, is in examples of (1) accidental dechlorinator overdose, and (2) very high %age water changes.

The other question, which I have stumbled over, is the amount of time the thiosulphate takes to react with the chlorine. This seems worthy of investigation, does it not? Or is everyone happy with the possibility that they might be regularly dosing their fish with chlorine levels of over 1mg/l, for an undefined period of time?

Another experiment here using a chlorine test seems appropriate to find out. I'm going to have plenty of test kits if I continue at this rate!

What is clear to me, is that there are more than one undefined and unanswered potential risk factors, involved with adding dechlorinator direct with tapwater.

 

[Tolak]

I regularly do large, 50% to 80% water changes. I also double dose with Prime in the winter, the water company does some funny stuff to the water here in the winter. They like to jack up the chlorine & chloramine, as well as adding more buffering agents. I have added triple the amount I'm sure, while trying to do 4 things at once with 2 hands. Never had a problem, I think any O2 scavenging is probably minimal, compared to the O2 being added as the tanks fill with a hose.

Now on angel fry tanks, the hose is a no go. One good blast & the turbulence causes massive deaths. On these tanks, which are 10 gallons, I do 50% water changes daily for the first couple of weeks. I fill a 5 gallon bucket with tap water heated by the water heater to tank temperature, add the usual double the amount of Prime, and trickle it in with a 1 gallon jug with a 1/8" hole drilled in it. Minimal aeration, as the water is just a trickle. If there was a major depletion of O2, this would be seen nearly immediately. Newly swimming angel fry don't leave much room for error where water is concerned. This is real world experience, not some wizz bang engineering/chemistry formula. According to engineers, a bee shouldn't be able to fly. Since the bee doesn't know jack about engineering, it flies anyway.

I think a bigger point you are missing is the conversion of chloramine to ammonia using any thiosulfate. This will mess up fish faster & worse than any minimal O2 depletion. More hardy fish will tolerate a temporary ammo spike, sensitive fish go from swimmers to floaters in no time. I just helped out a buddy of mine who has been breeding angels a lot longer than me. He had been using Novaqua to dechlor, but this winter the water was exceptionally nasty. I gave him some Prime, told him to double dose, problem solved. Novaqua doesn't deal with ammonia, he was getting an ammo spike that was more than his filtration or fish could handle. Anyone on a municipal water supply should assume they are using chloramine, if they aren't, they will without letting the public know. Use a dechlorinator that contains sodium hydrometanesulfonate to convert ammonia to ammonium if your pH is 7.0 or higher.

As far as the quickness of dechlorinators neutralizing chlorine & chloramine , it takes about as long as it takes to mix some chocolate milk powder into a glass of milk, and looks about the same when doing so. A couple of years back we had a really neat demonstration given by a rep from Tetra at one of the club meetings. He had a yellow tagging agent that dyed chlorine & chloramine yellow. This was used to demonstrate the effectiveness or lack thereof between different brands of dechlorinator. An effective dechlorinator takes only seconds to work, the less effective ones take triple or more the dose, and even then leave some chlorine/chloramine.

I think the biggest concern should be your water company, a government run agency. It's packed with patronage jobs, you get hired by who you know, not what you know. They err on the side of caution, dump in extra chlorine & chloramine to make sure the public doesn't get dysentery or some other nasty disease. The aquatics community is small compared to the general water drinking public. If your fish o.d. on chlorine they don't care. They routinely load up the system later in the evening, knowing that water will mostly sit in the lines, to start being used early on a work day by people getting ready for work. I can smell the chlorine good & strong late in the evening, me & my nose never took a chemistry class. This is a regular occurrence if I get stuck late at work, and end up doing midnight water changes. It's triple the dechlor in those cases, and the fish do just fine. In those cases any O2 problems should be triple those of a normal dose. Maybe the fish know chemistry like the bee knows engineering.

 

[andywg]

Jules, you are the one questioning common beliefs here, therefore it is really for YOU to provide evidence of what you have been told by (as far as I can see) one person. You have provided no scientific basis for how you believe TS to react with oxygen. We have all seen the chemical equations of how TS reacts with chlorine/chloramine. Until you produce one that actually shows how this process will occur, I will take it with an extremely large pinch of salt.

Do you not think it strange that a number of people (some scientists) give you reasons why they feel this reaction cannot happen, yet because one person told you otherwise you instantly question them, and not the solitary man? To turn it around, maybe you are looking for more risks and unanswered questions than there are to hope to be some kind of pioneer?

The rest of us, and the web, cannot find any examples of what you are saying can happen. Explain exaclty why the chlorine has an affinity to oxygen. This is the first thing you must do in your quest.

You also have avoided my point that it would actualy appear that the ST stays in the water awaiting new chlorine to remove. This information comes from people with swimming pools and chlorine meters. How would it do this if it reacts with oxygen in the absence of chlorine? I would be extremely surprised if it can react with the oxygen and prevent other organisms from using it, but once chlroine is available it releases the oxygen and then reacts witht he chlorine.

To sum up, considering how sensitive the fish that a number of keepers on this forum keep are (think all the rays etc) I doubt this is at all a problem. I severely doubt my fish could actually survive weekly changes involving 30% chlorinated water.

And I would severly doubt that if the de-chlor really took that long to take effect, that my fish would swim happily under the flow of water from the tap.

So, again, I ask you to prove what you feel is the positive (TS reacts with oxygen) rather than asking the rest to prove the negative (which, like most negative proofs, is so much harder - if not impossible to do).

 

[adam98150]

What if you never dechlorinate your water? What if you just changed your old water to new? How long would it take before the fish start to get sick/die?

 

[Jules H-T]

@ Tolak, great post, I found that really informative and provocative. Particularly the demonstation of the chlorine removal, the notes about your treatment of your fry, and the suggestions regarding ammonia production.

@andywg, you've got me wrong, I'm no wannabe pioneer. However I'm not an "ah OK this is how it's done so it must be right" kind of guy either.

A professional whose job it is to look after the water chemistry of our supply is who told me about oxygen depletion, not some random person. I tend towards giving credibility to a professional, but that's just me. The engineering debate I posted to earlier also mentions it. The following (look at the dechlorination section) also does: http/www.aquatext.com/list-d.htm

You say "a number of people (some scientists) give you reasons why they feel this reaction cannot happen". Who has given reasons why it cannot happen? I've seen comments that it doesn't, but that's different.

Clearly sodium thiosulphate is a reducing agent, and clearly the oxygen is available for reduction.

I have said before I would like to find out by experimentation, and I will reitterate that all I was doing was suggesting that the reaction was on the table and warranted investigation.