I sure see a lot of growers have bad pH problems from re-using tubes, tanks, and pumps. NEVER re-use a tube and those pumps can hold pieces of dead root in the filters.
Oh yeah, I have a 50ft. roll of tubing that i use to replace the tubing every grow. Blue tubing even
I pull everything on the hub apart. I do reuse everything. But I also let everything soak in a mild bleach solution AFTER a very thorough wash with a soft bristled vegetable brush and an old toothbrush. Make sure to pull every piece of the pump assembly apart and wash the crap out of the filter. I actually soak the filter in a separate cup of a higher concentration of bleach. Seems to be the main place bacteria would hide in. Then I rinse everything. At least ten times, then let it air dry in a clean sanitized room. I have a ozone generator that I will use after I scrub my room down and treat it with permethrin. I let the ozone generator run for 20 min an hour in there. It seeps into every nook and cranny in the room and kills all bacteria, virus, or mold of any type. It COMPLETELY sanitizes the air of the room. I let all my equipment (res, cover, net pots, pump, hoses I will be using for the grow) air dry in the room. I also buy new airstones, which I have to go out and get right now actually.
As a side note, the ozone generator isn't left in there. 20 mins of ozone could potentially be dagerous for the plant if its in too close proximity to the ozone outlet. Although I was thinking, If you were to have a pythium problem I bet that if you bubbled ozone through the water it would kill all the bacteria and not harm the plant. As long as you only did it once or twice. for about 10 min.