The problem with the WL tanks is they're all sealed up almost, and the place you add chemistry is really narrow--it's like the size of a liter soda bottle or a little bigger. It's actually a threaded PVC pipe with a screwcap into this acrylic tank. You can ruin those tanks by overtightening the caps. The 4E can be maintained almost entirely off parts you can buy at plumbing shops, except for the electronics. But the tanks are really fragile and if you get anything in there that you can't get out, you're screwed. We drained a tank once, for like 30 seconds and cracked a heater probe actually. It was an accident, but that was like the death knell for processing for awhile. You could stick a bottle brush down in there & break one of those probes and be out $$$. They're really simple machines & work great, a delight to use. Compared to Jobos, they're like miles above any rotary processor--even those autolabs. But those tanks need to be handled with care...a new WL Model 5 will set you back almost $20K, you can get these rebuilt 4Es for about 5-10K. You can get them used for probably around 750-1500. we use CLR in our Intellifaucet--it gets all gunked up and won't work--so you take these valves out & soak them in CLR and rinse them off. As long as the electronics stay dry, it's okay. I don't know what it would do to the WL, but those tanks will be tough to get at inside, all the corners etc....whatever you pour in there, has to go out through either a siphon, or pumped through the processor, so it can't contaminate anything along the way....I don't know if I would worry about it that much, unless it was caked in there. The other processors I use are pretty gnarly inside, Ii almost hate to touch them to load in chemistry, and it only makes prints worse when you actually try to clean out the tanks. It loosens up all this crap that otherwise never would have been a problem. If a roller or a reel or something touching a print or film is dirty, this is a problem, but tanks can sometimes just get stained.