I just wanted to share a little something here as I read many people are having a similar issue as me. I have a IPV2 and the ohms were jumping all over the place and it took me a while to track this down but it came out to be no issue with my tanks at all. In fact it is a connectivity issue with 510 connector to the box itself. I have tried soldering it twice now and it fixes the problem for a short time, probably due to my sub standard soldering ability. I will probably have to find a much better solderer to run me a wire from the screw where the ground wire is soldered on to the bottom side of the 510 to correctly fix the problem.