Well there are a few things I know of that are good for sanitizing.
1. Bleach
2. H2O2
3. Boiling water
4. Steam
I haven't used steam as a sanitizing agent yet, but the steam mop my mom got to clean the kitchen floor has giving me some ideas. There are various hand-held portable steam cleaners on the market, and I bet they would do a good job of sanitizing the inside of tubes if adapted right, as well as used on them long enough (10-20 min).
But first I wash everything with soapy water and a scrub brush (except the
growing medium). Then depending on what it is I need to sanitize, I'll use either bleach, boiling water, or H2O2. For
grow rocks, I'll let it dry out real good first to let all the organic material (roots etc.) dry up. Then I sift it out as best as I can. And soak it in water again and take out everything that floats. Then I rinse them off real well to get out all the organic material out, and soak it in a white vinegar/water solution for a few days to get off the built up mineral salts (string it up at least once a day), and then rinse it again. Then to sanitize it, I soak them in a bleach/water solution overnight (string it up a few times along the way). Then I rinse it out a few times, and if it still smells like white vinegar, I'll probably soak it in boiling water a couple of times to loosen up/dilute the white vinegar smell. Then let it dry out and store it dry for a while before I reuse it. Some day I may build a steam box for things like that, but I'm just not a fan reusable growing mediums anymore.
For the pumps, I take them completely apart and wash them in soapy water with a scrub brush. I don't usually sanitize them unless there was something in the water. But if I do, I usually soak it in straight H2O2. I also wash the air stones in soapy water, then soak them in straight H2O2 too.
The flexible vinyl tubing I let completely dry out so that anything inside drys out and sticks to the tube. That makes it easy to just flex the hose and break it off the inside of the tube. Then I flush hot water through it, and soak it in bleach water overnight, making sure the tubes get filled with the bleach water solution and all the air pockets are out (for complete coverage inside the tubing).
For PVC tubing I'll hook up an old
pump, and pump bleach water through it. And for anything too big to soak in bleach water or H202, I'll wash it completely with soapy water and a scrub brush. Then fill a spray bottle with either bleach water or straight H2O2, and spray it down completely with it (repeatedly).