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Water changes causing fish deaths

Myrkk

Fish Crazy
Joined
Jul 26, 2017
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Location
Scotland
I’ve not done a water change in months now as each time I did some fish died. I could not get an answer anywhere as to what was causing the issue. Happily I ran into a guy t’other day who finally gave me an answer…chloramine. As I may have mentioned, ahem, we moved last year to a more rural village and it seems they put chloramine in the water as well as chlorine.
Answer - put more prime in the water at change time… such a simple answer to a very gnarly issue.
 
Water companies use chloramine in drinking water because it stays active for a lot longer than chlorine does, and it is supposedly safer than chlorine, however I doubt that. Unlike chlorine that comes out of water by itself over a few days, chloramine remains in water for months and is active and killing microscopic organisms during that entire time.

Chloramine is a mixture of chlorine and ammonia. You normally need a double dose of dechlorinater to break the chlorine ammonia bond and neutralise the chlorine part. You then have to deal with the free ammonia. A lot of dechlorinaters used to treat chloramine have additives that either convert the ammonia into less harmful ammonium for about 24 hours, or they bind to the ammonia and stop it being poisonous for that time. During this time the filter bacteria should convert the free ammonia/ ammonium to nitrite and nitrate.

If you test the tap water and get an ammonia reading, then the water company has added too much ammonia when making the chloramine.

Ammonia in tap water is toxic to all animals including people and most people should use a carbon filter to filter their drinking water.

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Glad to hear you finally worked out why the fish were dying :)

I had a similar problem years ago with fish dying after water changes. I had chlorine in the water supply and used a dechlorinater. After years of complaining to the water company they finally sent someone out to test the water. It had 7.5ppm chlorine in. The maximum safe legal limit is 2ppm of chlorine. Basically the water company was overdosing chlorine in our water supply and even a double dose of dechlorinater and letting the water stand for 24 hours wasn't enough to get rid of all the chlorine.
 
WOW, that’s good to know Colin, will test the water and see what comes back. I generally only drink tap water or boiled water so might have to invest in a filter for it (as well as get in touch with the local water company)
 
Well spoke to soon. Did a water change yesterday, double dosed the prime and….

Almost all of my fish are dead this am.

Tested water, pH 6, ammonia 0, have put some bicarb in the tank and am hoping they’re alive when I get home as I can’t not be in work this am. Argh

To say I am upset and p $$ d off is putting it mildly.
 
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Oh noooo! 😱 what a nightmare!
 
Just been told you can get a chloramine filter to attach to your hose. Going to try this.

Spoke to the water company this am and they’ve sent me their recent water test results. Going to take it in to the Lfs who have a new guy there, the one who told me about chloramine and see what he thinks of the water parameters.
 
Post the water report here too.

Filters that remove chloramine are simply carbon filters. Reverse osmosis units normally have a carbon cartridge that helps remove chemicals and heavy metals from water.

Have you tested the tap water for pH, ammonia, nitrite, nitrate and anything else you can test for?

Are you dechlorinating the new water before adding it to the aquarium?

Are you using Prime dechlorinater?
How much dechlorinater are you using (double dose)?

What buckets and hoses do you use to drain and fill the tank?
Are the buckets specifically for the fish tanks and has anyone else used them for something not fish related?

Do you use moisturing cream, hand sanitiser, perfumed soap or anything that can leave a film on your skin? These can wash off and poison fish.

Do you have an airstone bubbling in the tank?

How much water did you change?
 
I know it doesn’t fix your water issue, and sorry for your losses… maybe you should start collecting rainwater, unless you are too tank heavy, like I am… it’s been an expense, but I’ve been so happy with my water since installing an RO unit for my tank water, and my fish have flourished
 
Post the water report here too.

Filters that remove chloramine are simply carbon filters. Reverse osmosis units normally have a carbon cartridge that helps remove chemicals and heavy metals from water.

Have you tested the tap water for pH, ammonia, nitrite, nitrate and anything else you can test for?

Are you dechlorinating the new water before adding it to the aquarium?

Are you using Prime dechlorinater?
How much dechlorinater are you using (double dose)?

What buckets and hoses do you use to drain and fill the tank?
Are the buckets specifically for the fish tanks and has anyone else used them for something not fish related?

Do you use moisturing cream, hand sanitiser, perfumed soap or anything that can leave a film on your skin? These can wash off and poison fish.

Do you have an airstone bubbling in the tank?

How much water did you change?
Will retest tap water tonight and post results. Took 3 small bottles of water out of the tank before I dosed it with bicarb this am so will get that tested comprehensively at the lfs.

Prime dechlorinater used at double dose for the size of the tank i.e. 200l = 4 caps spread over the 5 buckets of water that got replaced last night. Water always treated prior to putting it in the tank.

Due to the issues I’m having I only changed 5 buckets so around 1/5th of the tank as didn’t want to kill the fish (slaps self)

All fish tank stuff is kept separate and only I use it and only for the fish tank

I use sterillium hand sanitiser at work but had 2 days off so no film left on hands from that.

No airstone in the tank. It’s an under tank filter with a water bar across 50% of the surface that streams water down to agitate the water surface and some that are under the water surface to create a current. I do have an airstone but didn’t replace the air pump when it died.

Had to replace the tank heater at the weekend as the previous one died last week so the fish had a period of cold water stress.

Water report added
 

Attachments

  • Water 202303 Rosebery A Last 12 Months.pdf
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I like the idea of catching rainwater, not like we have a dearth of it up here in Scottieland. Thinking of RO water too, need to research exactly what is involved.
 
Did any of the fish survive from last night?

When you add dechlorinater to the buckets of water, how do you add it (add some dechlorinater to the bucket then fill it with tap water, aerate for 5 minutes and add to tank)?

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You have a few heavy metals including aluminium in the water but in low doses. The rest of the water report looks ok. Rain water or reverse osmosis (r/o) might be an idea and see how it goes, even if it's only temporary as a test. If they still die after water changes using rain or r/o, then it's something you are doing.

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Reverse osmosis units are basically plastic cases with various filter media and membranes in that can remove minerals, chemicals and heavy metals from water. You connect a water source to the inlet of the r/o unit and the water is forced through these different media. At the end of the r/o unit you get two outlet hoses. One hose is for the pure water and the other outlet hose is for the waste water that contains all the impurities. Good r/o units have a 1:1 ratio of pure water vs waste water. So for every one litre of pure water that you get, you get 1 litre of waste water that can be used on the lawn or let it go down the drain. Lesser quality r/o units might have 2:1, 3:1, 4:1 or worse ratios whereby you get 1 litre of pure water and 2, 3, 4 or more litres of waste water.

If you get a r/o unit, get a good quality one with a 1:1 ratio or better if they make them (I don't know of any that are better than 1:1 ratio).

Some r/o units can be fitted to a normal tap and used when needed, others need to be plumbed in, but most just get put on a tap with a threaded fitting.

R/o units produce water slowly, a few litres per hour. Bigger units produce more water per hour but you will need a separate storage container to collect the pure water so you can use it for water changes.

Pure r/o water should not contain any chlorine or chloramine and won't need dechlorinating.

You might have to add some mineral salts to r/o water to increase the GH and KH, depending on what species you keep.
 
I start filling the bucket and then add the dechlorinator as the bucket begins to fill so it gets mixed through the whole of the water.

Probably more like 3 mins it gets left than 5mins

There are 4 fish left this am that I initially thought were dead. The Cory had started to swim around and darted to the top at one point for air post bicarb adding. The other 3 were long finned calico bristlenoses that were squished up against the tank heater.

Was going to add more bicarb tonight if they’re still alive and order some RO water off amazon (if they do it, I’m sure they will)

Will do another 5 buckets water change and see how that goes.
 
I start filling the bucket and then add the dechlorinator as the bucket begins to fill so it gets mixed through the whole of the water.

Probably more like 3 mins it gets left than 5mins

Will do another 5 buckets water change and see how that goes.
I would add the dechlorinater to the bucket before you start filling it up with water. When the bucket is full, put an airstone in it and let it bubble away for 5-10 minutes just to make sure the dechlorinater has had sufficient time to come into contact with all the chloramine.

I wouldn't do another water change just yet. If the fish are in a weakened state from being poisoned, doing another water change with the tap water could kill the rest of them.

I would wait a couple of weeks and either do a 10% water change and see how they go. Or get a reverse osmosis or even just a carbon filter and run the tap water through that, then try the filtered water for a water change. If possible, dechlorinate the tap water and then put it through a carbon filter. You can run a power filter full of carbon on a container of water for 24 hours and then try that water for water changes.
 

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