La Marzocco Linea Mini black stuff in the water tank hose

#1: Post by **Ahmad H.** » June 6th, 2021, 6:46 am

Hello,

I started noticing some weird black stuff inside the hose connecting to the water tank. I am not sure if this is coming from the water tank or something that is coming from the pump (not likely). I use a RO system that is within standard water. Any idea what could this be?

Maybe coffee that found it's way in the tank? (The grinder is next to the machine). Maybe it's carbon?

#2: Post by **israguard** » June 6th, 2021, 7:03 am

Good morning,
My initial guess regretfully is that this is a type of mold and absolutely not coffee. Again.. guess as I have seen this in other clear/plastic pipes and fittings especially in bathrooms and such.

Either something is in the water... or machine sits idly too much. But that's not coffee.

Get a new hose as cleaning this will simply be a pain in the rear.

Again... it's my opinion only.

June 6th, 2021, 12:29 pm

Curious, is that water hose for the steam boiler or the brew boiler?

June 6th, 2021, 12:44 pm

It's between the water tank and both boilers. It's feeds water to the machine.

#5: Post by **JRising** » June 6th, 2021, 2:33 pm

That's a weird looking hose, it doesn't look like silicone. Is it the original hose or some fish-tank hose or something? (I don't know the Linea well).

If it's silicone, it can withstand just about anything you use to clean it. Dish-soap and water would do, peristaltic stretching and shoving to pass a soaped up pipe cleaner through the hose would certainly clean it out (if it is silicone. Looks way too plastic and clear in the photo).

#6: Post by **israguard** » June 6th, 2021, 2:40 pm

Looks same as mine
I'd replace it... it's the simplest of hoses.

Drop the metal fitting in boiling water.

This is mold

June 6th, 2021, 3:40 pm

Thanks guys.

If this is mold, where did it come from?? I will take out the hose and clean it with chemicals as well as the water tank.

June 6th, 2021, 4:25 pm

A little Hydrogen Peroxide diluted with water works wonders on mold. Let the parts sit for a while in the solution and it will kill the mold.

Mold could be from a few places. Maybe living organisms in your water... like well water, or could happen if you don't use your machine very often. Probably a combination of factors.

What kind of water do you use? How often do you fill the water tank?

June 6th, 2021, 7:00 pm

Rather than using any chemicals, you might want to try just giving the water reservoir a good cleaning. Then fill it with distilled water mixed with 3rd wave water espresso mix.

Or have a espresso repair shop safely clean it. That's such a big investment I wouldn't skip on experimenting with any chemicals

June 7th, 2021, 12:13 am

I use a 6-stages RO water filtration system. I put the water in a glass jar and keep it ready for when I need to result the tank. I refill the water tank once every 2-3 days.

I will use dish soap to clean the tank, glass jar and the hose. I don't want to use any strong chemicals as mentioned. And will let them sit in the solution.

Would that be sufficient? Hopefully this won't happen again.