Any water paramater experts about?

[Cobraxassassin]

That was my mistake. I read 7.4 in the original post but that was for the aquarium. However, if the tap water is coming out at 6.8 and the tank water pH is dropping rapidly over a week, then something should be done to buffer the water a bit to slow or stop the sudden pH drop.

Buffing the kh every 3 weeks has stabilised it completely, I dose the exact same amount every 3rd water change the ph never changes now, only the kh drops. So after 3 weeks I buff it back to about 8 and is working great. Where as before the oh was dropping to below 3 or 4 after a week or 2 with a kh of 0

 

[Byron]

Buffing the kh every 3 weeks has stabilised it completely, I dose the exact same amount every 3rd water change the ph never changes now, only the kh drops. So after 3 weeks I buff it back to about 8 and is working great. Where as before the oh was dropping to below 3 or 4 after a week or 2 with a kh of 0

I confess I am confused about this. If you are adding anything to the water it is likely able to diffuse across the cell membranes and is therefore entering the fish. Soft water fish do not need this, but more importantly it is probably making their life more difficult. What are you adding? And do you have a test to actually measure pH so low? I am thinking it must be a digital pH meter, as no basic tests I have come across measure below pH 5.

 

[Cobraxassassin]

I confess I am confused about this. If you are adding anything to the water it is likely able to diffuse across the cell membranes and is therefore entering the fish. Soft water fish do not need this, but more importantly it is probably making their life more difficult. What are you adding? And do you have a test to actually measure pH so low? I am thinking it must be a digital pH meter, as no basic tests I have come across measure below pH 5.

I fought for 8 months with the tank, ammonia spikes all the time constant water changes every fews days weeks on end eventually I lost the tank of fish,

My ph was always 6 on the api master test kit. So I purchased a digital ph test meter and the calibration liquids and the ph was 3. I recycled the tank and added fish again (8 neon tetra) and it always drops back to 3 or 4, so I began buffering the kh with seachem alkaline buffer. And the ph has now stabilised with no ill effects and the fish are all healthy. The oh hasnt moved since I started buffering the kh. But every 3 weeks ish I need to buffer again as it drops with water changes and the natural cycle. Over 2 months I added another 8 neon tetra and just added the ottocinclus and All is good

My tap water sucks...

 

[Byron]

I fought for 8 months with the tank, ammonia spikes all the time constant water changes every fews days weeks on end eventually I lost the tank of fish,

My ph was always 6 on the api master test kit. So I purchased a digital ph test meter and the calibration liquids and the ph was 3. I recycled the tank and added fish again (8 neon tetra) and it always drops back to 3 or 4, so I began buffering the kh with seachem alkaline buffer. And the ph has now stabilised with no ill effects and the fish are all healthy. The oh hasnt moved since I started buffering the kh. But every 3 weeks ish I need to buffer again as it drops with water changes and the natural cycle. Over 2 months I added another 8 neon tetra and just added the ottocinclus and All is good

My tap water sucks...

I can only point out some factual issues here. First, the KH buffer is not needed and the addition of any additive can weaken the fish. There is no need to buffer their water, they evolved to function best in basically zero GH/KH and an acidic pH. Providing this environment is not going to cause them to weaken and die.

Ammonia did not kill the fish if the pH was acidic; ammonia is ammonium in such water and this is basically harmless. Plants will assimilate it as their preferred source of nitrogen.

The fluctuating pH being caused by your buffering is much more harmful to the fish than just leaving it alone.