Maybe not a good idea bro . . .
TUMS is calcium carbonate (CaCO3), a weak base which neutralizes stomach acid (HCl).
If I'm not mistaken, the reaction creates a calcium chloride hydrate (CaCl*X H20) where X is the number of water molecules attached.
Whatever. None of that above really matters for anything much, but the point being that it is possible that the TUMS may NEUTRALIZE or REACT WITH your THIOCITIC ACID, rendering it ineffective. It's conjecture on my part . . . Par, Pat, Bill, anyone else want to comment?