Quote Originally Posted by Zeeflyboy View Post
What cad program are you designing in? I can't imagine you need to use an STL to surface area calculator, should be able to pull that info straight from the CAD program.

How big is your bath? Will splitting in two and diluting with 1L bring you to something under 10%?

Fusion 360 but can't work out surface area for some reason.

I have 5L tubs. Only 3L of water plus added ingredients.
By weight I have 3000g of water and 400g of 85% acid. So that is 7.5% of 85% acid?