Review on Apera Instruments AI209 Value Series PH20 Waterproof pH Tester Kit: Unmatched ±0.1 pH Accuracy! by Onsommoshit Mathews

I ordered the first block in mid July after my own engine started making noise. When I received the unit it was scratched and looked like it had been used, returned and repackaged. I did not install the unit and requested a replacement which was processed quickly. After running the second unit for 2 weeks the motor started making a horrible squeak so I requested another replacement which again was processed quickly and shipped with a delivery time of 1 day. So far the third device is working fine, but I've contacted Hagen (manufacturer of AquaClear products) directly if I'm still having problems. Turned out to be repackaged returns that were not properly inspected or tested. AquaClear products have an excellent reputation and high quality standards which leads me to believe that the Revain camp may have process issues. As a long-standing and very satisfied main customer, this is a very unusual situation. When you order a device, keep your old one just in case!