Low Iodine - Red Dyes - Colrite Stool Softener

I have to be on a low Iodine diet for the next three weeks in prep for a scan I have to have - Part of my BP routine is to take Colrite stool softener twice a day. However, colrite contains red dye in the outer gelcap. I consulted my pharmacy for a replacement and the only thing he found on the shelf was a laxative instead of a stool softener. Any suggestions out there? Should I take the laxative or skip that part while on the Iodine restriction? My BP works well as is, and I would hate to throw a wrench either way.

Low Iodine - Red Dyes - Colrite Stool Softener