[usmc121581]

Did you let them bothe soak in warm water to get the deposits of then read. If so go with the IO hydrometer. I have seen that with the sea test nes dozens of times. Every time they read high but yours is reading lower thats a first.

 

[usmc121581]

I seen that usaully ever time I seen that it would be the other way around. But usaully ever now and then you have to soak them in warm water for 15 mins because salt will dry on the needle and mess u the reading.

 

[usmc121581]

I would go with the IO one because I use that with a floating one in my sump and they are both dead one. But didnt you say one was used and one was new. I would use the new one for now. and next time you go to your LFS bring both of them and test them against theres and see which one is closest to what they read on these. Sorry could've of been better help.