Nonsensical gravity and abv readings

[krizo96]

The mead looks beautiful and clear, but the readings I'm getting make no sense to me.
OG was 1.115, I racked to secondary after about 3 weeks and the abv was around 10%, but the gravity was at 1.07 which seems too high to me.
Today I reracked after another month and the gravity fell to 1.065 but the abv is now apparently 5%. Something's not right here... any advice? Ideas what might have happened? Or more probably where I screwed up?

 

[AMessenger]

How are you measuring SG and alcohol?

A drop from 1.115 to 1.065 is 6.56% ABV per Abv calculator (https://www.brewersfriend.com/abv-calculator/)

 

[krizo96]

I'm using an wine alcometer for the abv and a hydrometer for the gravity.
I'm aware of that, that why it's so confusing to me. Last time I used this yeast it got to around 12-13% in around 25 days - and those results measuring results matched the ones from the calculator.

EDIT: I think I caught my mistake. The device I'm using for measuring the abv is usually used to measure abv in a completely finished wine, so it is unfit for measuring one that is still fermenting a bit. But why the fermentation slowed down so drastically after 3 weeks when there was so much sugar left, I still have no idea.

 

[harry_the_face]

Might have slowed from temp or weak yeast. Might need to throw in some more yeast.

 

[krizo96]

I doubt that because this yeast is really really resilient. I separated a small sample of this mead during the racking for an occasional sip and it stayed in the fridge for about a month because I forgot about it and when I found it was still fermenting. I could see the bubbles and when I opened it the plug literally flew away when I tried opening it. Closed it back up, a week later - same thing. I can't believe what temperatures it can endure.
My current guess is that I may not have oxidised it properly at the very beginning.

 

[bernardsmith]

Or may not have provided sufficient nutrients... or the pH may have dropped so low that the yeast are unable to effectively ferment the sugars...

 

[krizo96]

I think I added enough nutrients, actually added a bit more than I usually do. As for the pH, I measured it and it seemed fine at the moment, now it seems low at 3.3. A lot of the yeast still seems to be okay, but it might have been that.