The first time I used a lukewarm soak, I didn't have the heat gun, I went took the heat test with my finger and guessed. I had no idea what the actual temp was, I just new it wasn't warmer than me and that's what I perceived as lukewarm, lol. When I got the heat gun, I did my normal way of heating up water then shot the water to find it was 85 degrees.

I also wanted to add that if I was here asking for advice on something, I would definitely take Grif's advice over mine. He's been caring for them a heck of a lot longer than I have, lol.