Want to mix up Perceptol but thermometer nogo to 40 degrees

so, it says to mix it up at 40 degrees to make the stock solution.....but my thermometer only goes to 30 degrees....so is it crucial to mix at 40 degrees cos i figured id just trun on the tap and mix the water to make it hand hot in order for it to mix well......any advice welcome.....

It's not that crucial just try thinking laterally 40°C is only 2° above your own body temperature so think like that, luke warm is probably 50°C. Hand hot as in it feels warm is more than 50°C

Ian