No worries at all, it just says on the label - "Formalin 30%" and thats it.
The marine department of my LFS use it in all of their QT tanks when they have a new batch of fish before they put them out for sale.
Its Pond Medic Formalin 30% by Kockney Koi
O.K. - I ran the numbers and it looks like your formalin dose equates to 150 ppm which is spot on. Just be sure to aerate any containers very well when using formalin as a dip.
Jay