Bleaching Rock and need chlorine test strips - FREE or Total?

[Reefrock]

Hello

I am in the process of bleaching some old Dry Rock that was given to me. I am going to order some Chlorine test strips to validate the chlorine is gone (adding De-Chlor). I see there are two types...Free Chlorine and Total Chlorine. Which one should I order?

Any help is much appreciated!

 

[Timfish]

I've always used the nose test myself.