Beer Gas Question

I bartered for a Beer Gas Tank on CL and it is nearly full. Are there any convenient testing methods to make sure that it is definitely a beer gas blend? The mix is 75% Nitrogen / 25% CO2.

https://www.homebrewtalk.com/attachment.php?attachmentid=35117&stc=1&d=1317565553

https://www.homebrewtalk.com/attachment.php?attachmentid=35118&stc=1&d=1317565553

https://www.homebrewtalk.com/attachment.php?attachmentid=35119&stc=1&d=1317565553

I don't wanna push my stouts with anything toxic but wouldn't mind saving $30 on an early refill. Any suggestions?

Thanks,
Chris

That is definitely the stout blend. That sticker says 25% Co2 with balance nitrogen. You are safe.

I appreciate the reply. The guy that I traded with just had me concerned because he didn't use it personally. I think he owned some shopping centers and this was from a restaurant that closed and left it behind. If he had said he had it filled personally, I wouldn't have a worry in the world. None of the labels have been tampered with and I'm sure it would be tough to talk a vendor into filling the tank with a different gas... especially without changing the label after filling.