Very strange things happening to my tank with the water change

[ghurty]

A few weeks ago, I did a water change on a Sunday. The same way I did water changes for the past year. But a lot of fish (smaller ones) starting jumping to the top and then they died.
At that time somone suggested maybe the ph levels dramatically changed. But the levels from my tap were the same they always were. I did comment that I had used the water clarifier and somone said they heard that it may kill fish.

Flash forward to today. I did another water change and the exact same thing happened. This time I did not use the water clarifier. I have one of two solutions. The water company does something to the water on the weekends. Or there is an issue with the PH levels. I had taken the PH level from my tank before doing the water change, and while I may be mistaken it may have been 6.0. So if that is the case, why does the PH level of my tank drop over the course of two weeks.

Thank you

 

[Colin_T]

How are you doing the water change?

Are you dechlorinating the tap water before adding it to the tank?

 

[ghurty]

I am filling a big tub up and adding Prime. I then use that to change the water Up until a few weeks ago this is the way I did it without any issue.

I use a pump to take out water and then add the fresh water in None of the faucets near the tank support me screwing something onto it so I need to use the pump.

Thank you

 

[Colin_T]

Are you mixing the Prime and water for a bit before using it?
The dechlorinator needs to be able to come in contact with all the chlorine/ chloramine in the water and aerating the water & Prime for at least 5 (preferably 30) minutes is the best way to achieve this.

Is the Prime a new bottle or has the expiry date passed?

Has your pH test kit expired?

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Water companies don't do things to the water on weekends unless they have to. But they do sometimes work on the pipes during the week and they normally add extra chlorine/ chloramine after doing this. It then takes several days for the heavily chlorinated water to get to your home.

 

[ghurty]

Yes I mix it for about 5 minutes but not more. However for the past year I've been doing it without any issue .

I don't see any expiration on the bottle just a code number 89724.

The pH kit shows a number from the tap of 7.2. I had tested the pH of the tank right before the water change and I may have gotten 6. The reason why I said might, is that I did all the tests at once in different bottles The ammonia had spiked so I quickly did a water change. But unless I mixed up which bottle was which, then the tanks pH would have been 6. Which then may have explained why the fish got killed because of the jump in the levels from 6 (or below) to 7.2.

If that is the case, then I have to figure out why the pH levels dropped while the ammonia spiked

Thank you

 

[AbbeysDad]

I don't know where you live but in some cities in the northern US, failing infrastructures cause water mains to break, especially in the winter. Following repairs, this prompts warnings to boil water and likely for increased chlorine/chloramine additives to better ensure public health. There are also other reasons that increases may be required. A simple test strip may reveal the amount of chlorine in play.
If suspect, you may need to increase the amount of Prime. Alternatively, or in conjunction with, perhaps you could prepare the water a day or two before the water change, add the Prime and aerate to better ensure safe water for the aquarium.
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Also, for what it's worth, Although fine for the pool, I would never use a water clarifier in an aquarium. These work by binding small particles together so they are more easily trapped by filtration. This just can't be good for sensitive fish gills!
Good luck and keep posting.

 

[Byron]

One further thing...when testing tap water for pH you must ensure any CO2 is out-gassed or you will get a false reading. This can be done by letting a glass of tap water (no conditioner or anything else added, just plain tap water) sit for 24 hours. Or you can place some tap water in a clean bottle with a tight fitting cap and shake it very briskly for a few minutes. Then test pH. This is not needed for tank water, just tap water.

The clarifier might have been the issue in the first case when you used it, as this does exactly what AbbeysDad said. Presumably the next case is something else. Clearly there is something in the water that is toxic, whether chlorine, ammonia, high nitrate, nitrite, chlorine, chloramine, heavy metals...whatever. You need to check issue by issue to pin down the likely culprit. Use the recommended amount of Prime, but no more as this can harm fish too. If you have chloramine added to the water by the city, you need the larger dose of Prime as it instructs on the label.

Also, check with your water authority and see if they have made changes or are adding something.

You asked about pH lowering in the aquarium. This is due to the organic decomposition that produces CO2 and as CO2 increases it creates carbonic acid which lowers the pH. This is natural and normal, and not usually an issue. It also suggests your water may be soft rather than hard in terms of GH and KH. These serve to buffer pH changes, the higher the GH/KH are the more buffering capability to keep the pH stable. There is much to this issue, but we need to know the GH and KH and pH of your source (tap) water on its own. Within the aquarium, the higher the organics the more likely the pH will lower, again subject to the GH/KH. Larger water changes, vacuuming the substrate, keeping the filter well rinsed, not overfeeding, not overcrowding, any plant additives...all these are factors in the level of organics.