Hi Everyone,

My trusty Cimbali M20 Leva is plumb-in only, its connected to an external Shurflo pump (we rent, after all). The order of operations in the "plumbing" is:

2.5 gallon open bottle -> vinyl tubing -> filter -> Shurflo pump -> accumulator tank -> vinyl tubing -> ESPRESSO!

I'm getting mildew and/or mold forming in the vinyl tubing, especially after the accumulator tank. Any suggestions how to avoid mildew or mold forming in this system? I worry it will get moved into the boiler and will eventually be a huge pain to clean out. No doubt this is caused by a 4.5 liter boiler in a home environment, meaning the pump doesn't need to cycle on frequently.

I've thought about anti-microbial tubing (the silver "lined" ones @ $2.50 / ft), but haven't heard of anyone using this. Anyone have experience with these tubes or have alternative solutions?

I should also address the open bottle since it is literally open (just a tube into the top). Aside from just using a stopper w/ a hole, has anyone found any good impromptu reservoir options?

Assuming that you are on treated ("city") water I would suggest that the first step after cleaning everything out would be to install an airlock like used when brewing beer. You would need a cork with two holes - one for air in protected by the airlock, and one outlet from which the pump could draw.