It's strange as he has always steered me well in the past.
Hate to say I told ya so
Neons are one of the most common 'first fish' I'm not sure its an LFS problem more an industry wide problem.
They seem to die over night, one at a time. All my tests are ok except I've got high pH of about 7.6, does pH get higher at night? Could that be the cause of these fishes untimely doom or are neons like sheep, they are only born to find neecand interesting ways to die?
Nope they are just sensitive. On here you would be advised in the characin section that Neons should be in matured tanks. Then you will have to filter the different opinions of matured which will range from 3-6 months. Safe to say that it isn't just after cycling
Also don't get into the belief of the PH crash in this section or you'll end up getting some fairly lengthy posts explaining why there is no such thing
Ph is a relative measure that is influenced by other parameters. It is one of the other parameters that brings the Ph down that is the crash. possibly KH but I amd not really thinking that it is. Something else.
If Ph crash was a problem then we would all be having deaths in CO2 tanks. Also non planteds with no water changes where the KH drops over time (plants pinch the C) and then have a heavy water change (like I just did 60% after a year of no water changes) would suuffer a huge fluctuation of KH as the 0dKH water is removed to be replaced 60-40 with high KH lincolnshire liquid rock
I don't know what the real 'crash' is but I am pretty sure that the Ph dropping is caused by whatever is the real problem.
Yes it is normal for the Ph to rise at night and drop in the day in CO2 enriched tanks. It may be the same in CO2 addition tanks and non CO2. due to the levels of CO2 in the water in the day the Ph can drop to as much as 1.2Ph below normal. Once the solenoid cuts it off it will return pretty quickly (in the space of a few hours) to normal.
I've hooked the co2 back up us I've heard it lowers pH but what else will help? Was thinking of doing a partial water change with RO to take some of the buffers that would of been in the tap water out.
Leave the water alone. Stability in a higher Ph is better than fiddling to reach a 'managed' Ph. The 'high' Ph didn't kill the tetras. Many people who have them in higher than 7.6 will tell you that.
In the pictures is that your filter right down at the substrate? Move it up to just under the water surface to create a gentle ripple. That will promote gaseous exchange of O and CO2. Will mean you have to increase CO2 very slightly if it doesn't reach your desired level.
AC