i have these 2 ph meters, one is 1 year old the other 3 years old. they're both giving error when trying to calibrate, they were stored dry, as the instructions don't say anything about storage solutions. on the instruction it says if they dry out to immerse them in distilled water for 2-3 h, i did so overnight and they're still giving error, i'm gonna try immersing them for 12h in the 4ph solution as i've read it can help revive them. i will post a pic of the instructions and the ph meters. does anyone have experience with these cheap meters? how accurate are they? and how often do you calibrate them? as long as the margin of error isn't higher than 0.25 they're good enough for me as i can't afford the expensive ones
they work ok just test your tap water to get a starting point then before you use it again check either your tap water or some bottled water if it reads the same go by that i keep a bottle of spring water that is 7.2 and use that as a reference before i check my feed
been a few years... there is a hole to calibrate. you test it on reverse osmosis or distilled water. ph stays the same. i didn't use it much as i made my own water for shrimp tanks.
Lol........ I've been using the drops for decades without issue. Apparently this comment of yours is also inaccurate.
they're inaccurate, your own experience means nothing, nobody is gonna interpret the colors the same. the color scale is too similar where you can easily be off by 0.5 or more
Those meters are generally low end and do not last more than a year. I've owned many cheap ones like that over the years. Get a few BlueLab pH pens so you can check them against each other. Use the storage liquid and calibrate monthly. Or use the drops as MickFoster suggests or get a Litmus test kit.