Try mixing with a different source of
RO then. I have my own
RO/DI filter and also use Instant Ocean, and my
pH is constantly 8.4 without any kind of buffers added to it, with a +/- .01 flux because of lighting and stuff like that. The only thing it can be is your water source... unless somehow all of your testing methods are faulty, or you got a crappy bucket of
IO.
