15 replies to this topic

[dazzabozza]

Was just having a read of a Water Corp doc where they mention they mix chlorine and ammonia to form chloramines for water sent to Kalgoorlie etc (has been discussed a few times here).

Our metropolitan water is only supposed to contain chlorine. My question is if your were to add tap water to a tank that is cycling (ammonia is present) will this form chloramines? Or is a special process / reaction needed for them to bind?


Daz

[Mr_docfish]

The chlorine will not bind to the ammonia if you have used a dechlorinator (thiosulphate) or you have aged the water before hand. The thiosulphate in all dechlorinators will break the bond with ammonia, therefore releasing it.
The ammonia is added to the chlorinated water to make it last longer while in the pipeline going such distances in such temperatures.... this is the reason you will not have this problem here in the metro area, so there is no reason to use a conditioner/purifier that binds ammonia in the metro area.... there just isn't any added.

[dazzabozza]

So people who don't use dechlorinator or don't age their water run the risk of chloramines forming if ammonia is already present in the tank?

And if the above is correct will chloramines evaporate from the tank like chlorine does or is a dechlorinator the only method of removal?


Daz

[Mr_docfish]

chloramines will not dissipate from the aquarium as quickly as chlorine on its own - this is the reason they use chloramines in the wheatbelt - they want chlorine to last longer.

now I dont know if chloramines are more dangerous to fish than plain chlorine, but either way, the chloramines will be present for longer, so cause more damage.

[Shane_H]

Energy (eg heat) is required for the reaction to bond Chlorine and ammonia (to form chloramine).

So no, ammonia present in the aquarium wont create chloramine.

Shane.

[Mr_docfish]

Then how do the water corp get chloramine in the tap water??? they can't actually heat all the Giga litres of water on the way to Kal?.....

I have a list of chemicals that the water corp use in our tap water - and the list does not include chloramine, but it does include Calcium and Sodium hypochlorites as well as ammonium hydroxide and ammonium sulphate..... these are the two types of ammonia they add to the Northam treatment plant......Click here for PDF Download - if you want to check

It might just be that ammonia can link with Chlorine without the addition of added heating....

Just a thought...


And this added bit - from http://www.malawicic...rification.html
"Chloramines are typically generated on-site by the addition of ammonia (NH3) to water containing free Cl2 (HOCl or OCl depending upon the pH of the water). The optimum reaction pH is on the alkaline side; pH 8.4 (i.e., NH3 (aq) + HOCI « NH2Cl + H2O)
Chloramines are not highly disassociated in aquatic solutions (in other words, only minimally ionic). That fact, and their low molecular weight, makes them difficult to remove via RO (discussed in more detail below). The monochloramine form is the best biocide, and as is noted, is the dominant entity at pH 7 and greater. Since slightly alkaline waters are less corrosive, municipalities in many cases maintain the monochloramine form and reduce corrosion potential at the same time. Note that at an alkaline pH, chlorine exists as the hypochlorite ion (OCl), which has a higher oxidative potential than hypochlorous acid (HOCl), but is 80 to 100 times less effective as a disinfectant."

[Shane_H]

I think the metro scheme water is dosed with chlorine gas, which is why it disappears pretty quick when oxidised or left standing.

Chemical reaction for chloramines to be produced:
NH3(aq) + HOCl → NH2Cl + H2O

If it is chlorine gas (Cl2) in our water, but hyperchlorite (HOCl) (which is also a liquid or powder) is required for the reaction with ammonia to create your chloramines, then i don't think it can happen (at least in Perth metro).

Check this as my chemistry is a little rusty.

Chloramine is in a liquid form at room temperature. Not sure if you're joking about heating giga litres of water or not...but no, they'd just produce the chemical "chloramine" by bonding chlorine and ammonia through a reaction process, then dose the water with that chemical.

From wiki...
Chloramines are often an unwanted side product of oxidation reactions of organic compounds (with amino groups) with bleach. The reduction of chloramines back into amines can be carried out through a mild hydride donor.

Do most aquariums produce ammonium (NH4)? If so, would it be more difficult to break the bond for the reaction to take place? I guess it's possible....?

[Mr_docfish]

The water corp actually use Sodium hypochlorite as their main chlorine source (not very stable in high temps, strong light and extreme pH - so it gasses out very quickly).... and at Northam, they add the ammonia (as a hydroxide or sulphate - depending on the pH required).... since the water is at an alkaline pH (maintained by the water corp), the ammonia is in the ammonia NH3 form, not ammonium NH4 (this will form in acidic pH). This will allow for the bond to take place.... I am not sure what temp is required to get the best bonding rate, but I feel the water corp are hoping for the best with what they have got..... so you might be right in saying that high temp is required to get the highest percentage of bonding to occur - but this is not practical for the water corp.... Chloramine is not on their list (see PDF above) as the base product, but the required intermediate products are there in their list....
I have a friend that has done work for the pumping stations along the pipeline to Kal, and he has told me what the procedures are, and what chemicals he has seen.

In the aquarium, the ammonia can be in either form (NH3/NH4) depending on the pH..... in most cases the pH is above 7.0, so the ammonia is as NH3 = Ammonia.... which most probably will bond with any excess hypochlorite if present in the top-up water... though the damage done by either is about the same, so even if this is or is not the case, the chlorine will still cause some damage to the fish, regardless of whether ammonia is present.

On a side note......
For those people living in the vicinity of Mundaring/Sawyers Valley, keep in mind that the water from the Northam reservoir is pumped back to a reservoir in Sawyers Valley for distribution in the surrounding area - so Chloramine will be present in the water in those areas.

[Sinbad]

G'day Ollie,
We have a friend who is part of an action group currently campaigning against the construction of a large new water treatment plant in close proximity to Mundaring weir (on the site of the former forestry settlement, now the DEC complex and Hills National Parks Visitor Centre). Our friend was recently given a list of the chemicals to be stored and used by the Water Corporation at the new treatment plant by a person in that organization who is sympathetic to the action group's cause. The same chemicals are currently in use at established treatment plants. For your interest, and that of other forum members, here is the list; verbatim.

Chemical Name Physical State Concentration

Chlorine Liquefied Gas 100%
Ammonia Solution 25%
Flourosilicic Acid Solution 22%
Hydrochloric Acid Solution 32%
Sodium Hydroxide Caustic Soda Solution 50%
Hydrogen Peroxide Solution 50%
Sulphuric Acid Solution 98%
Carbon Dioxide Liquefied Gas 100%
Aluminium Sulphate Alum Solution 50%
Calcium Hydroxide Lime Hydrated Powder 85%
Potassium Permanganate Condy's Crystals 100%
Polyaluminium Chloride PAC Liquid Flocculant 83%
Ferric Chloride Solution 42%
Sodium Bisulphite Solution 35%
Ferric Sulphate Solution 40%
Sodium Hypochlorite Solution 100%
Ozone Liquefied Gas 100%
Carbon, Activated Powdered or Granulated 60%
Carbon Anthracite Coal Filter Medium 90%
Sodium Bicarbonate Soda ash Powder 100%
Sodium hexametaphosphate Calgon Powder or Flakes 100%
Polyacrylamide type Polyelectrolyte

[Juls]

No wonder growing up on a farm drinking rain water,
I cannot stand the taste of scheme water here in perth..

Water authority reckons Rain water is not safe for drinking... I think i'll take my chances.

I do have to say though, the tap water i do get at home is pretty reasonable quality,
in that it is PH 7.0 (exactly) and has 0 reading for ammonia and Nitrates,
however it does have a very slight reading for Copper.. which is a nuisance for my shrimp tank.
Seachem help me out with that one. I think i am lucky with that one, as i hear the northern suburbs are getting PH readings up to 9+!

Juls

[Mr_docfish]

Thanks Sinbad...
Well I might stand corrected here Shane, on the Chlorine addition - it looks like they intend to use Gaseous Cl2 instead of Na hypochlorite.

From my recollection of the use of liquid hypochlorite, it might have only been the country reservoirs where they add extra Cl in between the individual reservoirs to top up the Cl content..... it might be that they use Cl2 gas at Mundaring Weir to start with....

Now I have to do some research on the Metro area, and see what the preferred product is.... this has got me thinking again..... they never stick to one thing - they keep changing

[Ivan Sng]

Well in my other hobby/addiction, I top up the fish tank with water straight from the tap... with heaps of aeration and water turnover, it is believe that chlorine will dissipate quickly and it would not be harmful to the fishes... so far I have not lost any fishes that I can link to topping up the tank with tap water...

So the question is for a tropical fish aquarium can I adopt the same approach?? Somehow the idea of using a chemical (dechlorinator) to remove another chemical does not seem too correct to me. I intend to just do water top-ups without dechlorinator... would this be a problem??

[dazzabozza]

Gday Ivan

You're a Koi fan?

Here's a really good recent discussion about good water prep vs water conditioners - http://www.perthcich...showtopic=30113


Daz

[Ivan Sng]

Hi Daz,

Not exactly a Koi fan... Aquaponics to be exact... so Koi/Goldfishes will be "change-over" season fishes, but mainly rainbow trouts and barramundis and possibly Silver Perches as well once my other system is up... meant for consumption hence I do not use any water conditioners...

Thanks for the link, I will take a look...

Ivan..

[dazzabozza]

Aquaponics to be exact...

Sounds good Ivan. I'm going to see if we can get that as a talk/subject for one our future meetings.

Daz

[Ivan Sng]

More than happy to provide you with information if you require...