Has anyone have had experience with the cheapo Asian pH pen meter, purchased from an auction site? I had bought (ship out of California) one due to several of my tanks had below reading of 6.0 (using liquid API test). Wanted to get a more accurate number. Anyways, adjusted the meter with both buffer soln of 4.0 & 7.0 (these were lab types of buffer and not the ones that came with the pen). But when I read several of the tanks, they registered 1.4 & 2.2 (I am guessing no way). I did re-read the buffer soln and still read 4.0 & 7.0? Is there something I am missing? Or is this just a piece of junk? Without getting real expensive pH meter, other suggestions on how to get accurate readings on my tanks. One tank has CRS, CBS, PFRs and they are all fine. Another has betta, plants (liquid test read at 6.5, but meter read at 2.2) Also temp were around 72F.
Thanks for any help!