Watercooling Troubles

I just bought some Bitspower Compression fittings (1/4" ID x 3/8" OD). Along with that 5ft of Tygon tubing (1/4" ID x 3/8" OD). I was planning on using colored water for my loop, until my friend told me his bad experiences with it. Now, I want to buy colored tubing however, no one seems to carry RED tubing with (1/4" ID x 3/8" OD) fittings. So I was wondering if I could use (3/8" ID x 5/8" OD) or any other sized tubing for that matter, with the compression fittings I have.