I looked at the StraightEight site and they sell both green and red colored fluids. I would contact them and ask what the fluids are. They should be
1,1,2,2-Tetrabromoethane or
Acetylene tetrabromide; TBE
Specific Gravity 2.960
The specific gravity is important!
https://straight-eight.com/product-c...s/gauge-fluid/