interesting, after reading your post I did some looking too. I found specs on both the 'ink bird' and STC-1000 from what I saw they both have an accuracy of +/-1ºC (+/-2ºF) that is close to a 4º spread. IMO too much for plastic tubs, marginal for a PVCx but perfect for glass.

The Inkbird has an impressive hysteresis 0.1ºC so that would minimize the spikes IF the probe response is fast enough and doesn't do some odd behaviour coupled with the relatively slow sample rate (0.5s, the herpstat is 0.02s I think 60 samples per second)

The STD-1000 also seems to have good hysteresis (difference set) 0.3ºC. They didn't spec the sample times I can find. The probe response time is not in either specs typical it is too variable depending on the manufacturing process.

Are the probes of both units heavy or light?

one of the big issues with hydrofarms are the heavy probe the slow sample rates and in the old units the huge hysteresis, (2ºC!!!) They are IMO ONLY good as a back up nothing else.

I personally would not suggest one for a primary on anything but glass myself but they are certainly better than most of the reptile specific crap on/off units out there.

I am interested in them as a fail safes, i have been using hydrofarms but these look better and could be stacked easily. Where did you find the "InkBird" units?

http://www.tradeger.co.za/pdf/stc100...ing_manual.pdf
http://www.ink-bird.com/product/deta..._ITC-1000/id/6 (download manual)