Bad tap water. Why you need to test it.

Last Friday I did my weekly water changes on a number of tanks. In recent months I have got lazy about testing my tap water before water changes. Within 48 hours I had a black neon tetra in one tank swimming upside down, in another tank a garra rufa was stationary on the substrate and in another a gold gourami was jumping at the surface and in the same tank a lyretail Molly was shimmying.
The only thing all these tanks had in common was they had water changes on the same day.
I put all the affected fish in hospital tanks with fresh water the next day ( which I tested first and found to be ok ) and I'm glad to say all but one recovered. The Molly didn't make it.
I don't know what was wrong with the water but it's the only culprit I can think of to explain my problems.
I will now try to remember to test water before changes.
The moral of this story is don't cut corners when it comes to water testing.

 

How big were the water changes?

 

20-30%

 

Have you ever tested the tap water and found it to be bad in the past?

 

I've never found it bad as such but the parameters do vary seasonally so I have alter the ammont of equilibrium and sodium bicarbonate I add. Usually it's harder in the summer and Autumn and softer in the winter and spring however if there's been heavy rainfall it gets softer and the pH is lower. When it's been dry for a few weeks in the summer the water has nitrates of 2.5 - 5 whilst normally there are no traceable nitrates.

 

I've never found it bad as such but the parameters do vary seasonally so I have alter the ammont of equilibrium and sodium bicarbonate I add. Usually it's harder in the summer and Autumn and softer in the winter and spring however if there's been heavy rainfall it gets softer and the pH is lower. When it's been dry for a few weeks in the summer the water has nitrates of 2.5 - 5 whilst normally there are no traceable nitrates.

it would take a pretty big change in the mineral content of your water to affect fish that quickly. However, if your local water plant changed the amount of chlorine or chloramine in the water in response to a bacterial or algae bloom. that could very well have caused a problem that quickly. I suggest you contact your water supplier, tell them what happened to your fish, and ask them if they changed their treatment process in recent weeks.

If you are dosing your water with Equilibrium and baking soda, you should be testing the pH, GH and KH of your tap water frequently. Otherwise, your dosing could be wrong as the water changes seasonally.,

I have very poor tap water quality. My water is high in pH, high in alkalinity, high in pH, and contains phosphates. Furthermore, the water plant treats the water with chloramine rather than chlorine. Since the water is so hard, I use an ion exchange water softener to soften the water for showering and washing clothes, but the water has high sodium content which makes it unsuitable for aquarium plants. Thus, I installed an RO system to provide purified water for drinking, cooking, and aquarium use. For the aquarium, I remineralize the water as you do.

 

My water company uses chloramine but my water conditioner is supposed to deal with it. I always do double the recommended dose because I know my water company uses a lot.
I have the opposite issue to you, my water is too soft. In the winter it's almost like RO water, in the summer it gets a kH up to 1.5 and a GH of 2. The pH is usually around neutral.
I have considered an RO unit so I have a standard starting point but I have never got round to it.

 

My water company uses chloramine but my water conditioner is supposed to deal with it. I always do double the recommended dose because I know my water company uses a lot.
I have the opposite issue to you, my water is too soft. In the winter it's almost like RO water, in the summer it gets a kH up to 1.5 and a GH of 2. The pH is usually around neutral.
I have considered an RO unit so I have a standard starting point but I have never got round to it.

Remember that adding a water conditioner based on sodium thiosulfate with break the chloramine bond and then reduce the chlorine to chloride ion. However, the ammonia released from the chloramine will still be in your water. Many water conditioners also have chemicals to combine with the ammonia to make it less toxic until your beneficial bacteria can deal with it. However, you will still end up with nitrates in your tank. You might want to consider using zeolite filter media or ammonia removal pads to remove some of the ammonia before you add the water to your tank.

If your KH and GH are that low, there is really no need to consider using an RO filter. One thing you might want to do is to run your tap water through a carbon block filter to help remove the chlorine. That will make it better for drinking and for your fish. The carbon does not absorb the chlorine, but reacts with it to reduce the chlorine to chloride ion in a manner similar to the thiosulfate. Of course, you still have the issue with ammonia.

 

I have been using the same water conditioner in the same manner for years and I have never had ammonia issues.
It may be relevant that I have found they were replacing water pipes just up the road last week, this may partly explain why the water chemistry may have been abnormal.

 

I have been using the same water conditioner in the same manner for years and I have never had ammonia issues.
It may be relevant that I have found they were replacing water pipes just up the road last week, this may partly explain why the water chemistry may have been abnormal.

Good point. When they mess with the water pipes, they probably stirred up all kinds of stuff that settles out in the pipes.