It's just 1/4" polyethylene tubing. The different colors are just for identification, otherwise it's all the same. I ran my output from a kitchen cabinet, under the house to the tank in the living room. A distance of about 30 feet using the same 1/4" tubing. It's not in any conduit, but is attached to the floor joists and inside the insulation. It gets cold in the winter, but so far has never frozen.