When I check the ph and ppm of my plants, I draw the water out of the catch basin using a baster, and put it in a cup, up to about 1 inch deep. My Ph meter works fine (I purchased a set), but the PPM meter changes, depending on how deep the meter is dipped in the cup. If I put it to the bottom (so it will stabilize and I can take a reading), the values go up into the 4000 range, or goes off the scale. I found that if I drew water out using the baster, to a point where the sensor of the meter is just touching the water, it gets into an expected range. This doesn’t happen with the ph meter – no matter how deep I put it in, the value is the same.
I got a replacement meter from the manufacturer at no cost, but the replacement does the same thing.
Is this working correctly? I wish I had seen your recommended meter on your webpage. I’m tempted to buy it, but wanted to make sure. Is this meter working properly? The instructions are poor and appear to have been written by a non-english speaker. The person I reported the problem to didn’t understand me well. I’m at a loss here.
Tds, ec, and ppm meters are usually not that technical. It sounds like a faulty design. They should use 2 metal electrodes and measure the electrical resistance between them when placed in a solution. I suggest getting a different meter. If the ph meter is from the same company I wouldn’t trust that either. You can buy calibration solution to check the accuracy of both and that is something I suggest you do no matter what. These devices drift over time and need to be recalibrated. After about a month you’d be surprised how inaccurate they are.