How reliable and well built is the ph tester? Would you buy it again or recommend it to other hobbyists?
It's reliable to 0.1 with a +/- 0.1 tolerance (which is pretty much a given). So pretty accurate and in controls against other more expensive probes it came out with the same reading - occasionally it would be .1 out but that's it's tolerance so understandable really. The only issue as I see it with the cheap probes is that they require frequent calibration to ensure their accuracy - whereas expensive probes will stay highly accurate for a much longer period of time without calibration. Some people hate these things, others, like me, realise that they are only a cheap solution but that with some diligence in terms of keeping them well calibrated, they are accurate and last long enough to pay for themselves vs liquid tests, not to mention that you're not having to unleash that nasty stuff down into the drains, which inevitably ends up back in our drinking water.
It uses ATC - which is automatic temperature compensation - so you need to hold it in the water for a good 10-20 seconds to bring it to temp (initially) and this ensures a true reading. It still reads straight away, I'll do a video for you to see how it works, but as you swill it and it adjusts to temp it starts to settle on the reading. Some cheap probes won't have this and it's a PITA as you have to keep checking charts to see what reading = what at different temps. The one I linked you to is ATC.
Yes I would buy it again if I didn't have the money for a more expensive probe, but I've not had to buy a new one yet and it's still accurate. I've dropped it a couple of times, you just need to recalibrate it after a drop or hard bump - it's precision equipment, so it needs to be treated as such. Drops could kill it if you were unlucky, generally drops are more likely to increase the rate at which it loses accuracy, rather than kill it completely. It will need major calibration after a drop, like most precision kit.
I do recommend them, but on the understanding that it is a cheap-o version that
can be just as accurate as long as you keep it regularly calibrated (once a week is enough), but that it will need replacing eventually. Mines been used a lot and it's several months old, it still only creeps out .1 over a week period, sometimes not at all, when it starts creeping out by .3 then I'd think about replacing it. For the price and number of times used, well worth it IMO.
Go on ebay and search for - "ph calibration solution". There will be loads of sachet types, don't bother with these - you want the
bottled liquid (probably yellow) because you can pour it into a small container to calibrate and as long as the probe and container are clean, pour it back into the bottle for re-use. It's worth replacing this stuff once you think you've used the entire volume two or three times over. Oh and give it a good shake each week too otherwise you'll find it thickening up at the bottom and making loads of jelly like bits.
By rinsing the probe in pure water (I just use filtered fridge water) and drying it well after each use you will maintain it's accuracy for a longer duration.
Here it is in action, I haven't calibrated it in a while which is why it keeps jumping between the .3 and .4, normally it would have sat at .3 after it dropped but because it's creeping out it's at that borderline point where it flips from .3 to .4. Considering I've not recalibrated it in about a month (hasn't needed it) that's really pretty impressive that it's only just starting to creep by .1 .
http://s100.photobucket.com/albums/m15/ ... probne.flv