... .. . I have not been on *any* PC forums for a long while. Today I decided to try to log back into Tom's and finally I remember the name Techgage. Sorry about that, but Toms has been suddenly popping up in the lower right corner of my desk top. GRRRR .. have to figure out what snuk in to kill. Anyway, while on Toms, I notice that there are recommendations for flushing out the WC system. My big thumpers are WC and have been for a long while. They are never flushed and we are talking years. I rcvded the 2 systems from newegg on 4/21/2015. It probably took 2 or 3 days to get things put together that could be called "put together" as in running. I use distilled water or possibly RO/DI water from my marine aquarium system (pretty much the same thing, basically pure water as pure as can be had). No additives of any kind added, I think, maybe an anti-bacteria something. I know I have/had it but don't remembering using it on these systems. Anyway, it is news to me that these systems should flushed! One recommendation is 6 months. HA!!!! That must be for the OCD of us. My greatest concerns are how to blow out the radiators mounted on the back of the case. Part of my mitigation of keeping those nasty dirt collectors clean is to have them up on the back of my desk (carpeting is not your friend) and no animals in the office. Back in the day I could have probably weaved a new cat once a year from the fir collected. You would have thought that they slept & cleaned them selves in the cases. NOT! Back to flushing. This has not been done because there is no provision in the plumbing to accomplish. Well, it also never occured to me. When the radiator is more or less clean there is no over heating. My cleaning process to date has been a high powered blower (intended for cleaning out electronics) pushing air out in reverse of the cooling fans normal flow. Have to lug the heavy a$$ steel cases down 2 flights & outside so the office isn't made a dust storm. The question buried in this meandering, do people actually flush their system? One guy even said he replaced all of the tubing. Another commented that rigid lines do not need as much cleaning as the flexable. I say BS to that, FWIW.