Riddle me this Batman...

[gzeiger]

I wasn't familiar with the API pH kits - I've always used a meter myself when sufficiently curious. I rarely bother, as it just isn't a critical parameter in most cases. If you're breeding discus or neon tetras by all means test it twice daily, but I've been running seven tanks and haven't done a pH test in six years.

5.5 is in the "some effect" range, but doesn't explain all this. Nitrification can take place, and a tank will still cycle, in the low 4s.

 

[jessipanda]

On the API color chart, which I have in front of me, there is a value between 7.4 and 7.8 that applies to both tests. So yes, a value lower than 7.4 will read 7.4 on the high range kit but will read on the low range as the right value. Same in reverse.
But the OP states that on at least one occasion, there was a low range of 7.0 and a high range of 7.8. THAT should not happen.

Lol you're right, I didn't check it forgot it started at 7.4. But I must have missed where OP discussed those results... Oops! Guess I was more exhausted than I thought. That is very strange...something must be off.

 

[Autumnsky]

Still wondering what the tank temp has been at during this whole adventure?

 

[gzeiger]

Further information was provided by PM, and I must withdraw my earlier statement about pH. Figure out what it really is.

 

[Johny]

Gzeiger
You have made three previous statements, which one are you withdrawing?

Sent from my LG-H631 using Tapatalk

 

[gzeiger]

Although nitrification can take place at a low pH, the initial establishment of the cycle will be inhibited. A low pH may be the problem here.