<a href=showthread.php?s=&postid=8547436#post8547436 target=_blank>Originally posted</a> by Coralfreak
Wow, that is kinda high for a used AC2, did you get anything else with it besides the probes. You dont HAVE to replace them every year, you SHOULD, there's a difference(Its recommended to replace them every 12-18months I believe). I ran my last pH probe for almost 5 years..lol It still calibrated fine, so I saw no reason to replace it.