Hey!

We have a little bit of a problem with kitchen gear made of light plastic and the dishwasher. If you put them to wash on the dishwasher they usually end up brownish.

Is there any solution? Specially if they are already brown

Gosh the water in Zürich is full of lime…

Filters are not an option since we're renting.

Indeed, water in CH is pretty high in minerals. Add some CO_2 with a bubble machine and you have a better beverage than whatever bottle you can buy in shops

Concerning the dishwasher, read the manual. Somewhere, there should be an explanation of how to set it depending on the amount of minerals in water. I think it's carbonate hardness. Then google for Zurich water chemical analysis (https://www.google.com/url?sa=t&rct=...2HYAK_utLAlC7d) and you'll find the required parameter to set your washing machine.

Also relevant, put salt in the machine as indicated by the manual. Finally, are the dishes made for a dishwasher and which temperature are you using?

Try adding half a cup of white spirit vinegar, it does wonders. Wait until the actual washing cycle has started, open the door and throw it in - otherwise it will just drain away.

Try lemon juice? Citric acid is supposed to be good for removing rust, if that's what it is.

The problem isn't the regular dishes, but with things that are dishwasher safe and are made of plastic. For example plastic tupperwares or lids of glass tupperwares. Or for example of we just got a knife that is dishwasher safe and and the handle if white. The rugged part of the handle —as anti-slip purposes—has started to become brownish.

I'm not sure about the dishwasher… I bet an arm that it already have those settings on. Of course it has salt.

My believe is that things become brownish on the dishwasher —and other places—when the lime gets hot…

PS/ the manual of the dishwasher is in german… I've tried to find it on english, but this is a swiss model. ¬¬

Perhaps try running the machine on a lower temperature programme?

How often do you do this? Each cycle? Or just once in a while to spruce things up?

Yeah… it's something I've been thinking to wash things with plastics, but you have to think that dishwashers aren't washing machines and they don't have "just tap water option". If you want to remove soiling from dishes in the end you need hot water. More hot or less hot, but hot water. I think lime gets brown with hot water from the tap…

For us is really a headache because it's the first time in our lives that we have to face this issue…

Concerning temperature, for sure things will change color in the 70+°C program. I use the 45°C program at home and no problems.

Never assume the machine is properly set, for example a child living there before could have played with the buttons.

Never hat this issue. The only brown stuff I know is rust. Might come from a rust prone piece or from the dishwasher rack itself if the coating is no longer intact.

PS: If you tell us make and model we can find a English manual or at least translate the very basics.

There are lots of minerals that can leave red/brown deposits, not just iron. We get that here (Valais) not in the dishwasher, but sinks and toilets, particularly noticeable recently after we'd had groups of people in our apartments for a couple of months who clearly hadn't been cleaning frequently enough, if at all. Cleans off easily with a bit of hydrochloric acid, available in most French supermarkets, taking care to rinse well to avoid damage to rubber or metal components.

Dishwasher-wise, we have always had problems at our Alsace house, not very much elsewhere, although it's more normal cloudiness there, not red staining. Not helped by the fact of using black tableware for the last 15 years or so. I find that a very occasional run-through of said crockery with a dishwasher cleaner can help remove it, but care must be taken as they can be quite corrosive. Vinegar also helps, as previously mentioned.

But the biggest issue seems to be the salt dispensing, where the salt in the 'tank' seems to get compressed and doesn't properly soften the water. Or maybe it just doesn't dispense enough for the very hard water we have there. From time to time I'll stick a spoon down into the filler and really stir it all around, and this seems to set the machine on the right track for a while. Worth a try, and perhaps you can test the theory by just manually adding a little salt into the machine in the wash and rinse cycles.

As far as I understand how the salt works in a dish washer this will not work.
The dishwasher has an ion exchanger, a water softener which works by replacing the Ca ions in the water with Na ions. This does not work by simply throwing salt in water or inside the dishwasher. The salt must go in the correct compartment.

Every so often the Na ions in the ion exchanger are depleted and it is saturated with Ca ions. The exchanger must be regenerated by flushing it with a Na ion rich solution: Salt brine. Hence, the German term "Regenieriersalz" for dishwater salt (It is just plain NaCl w/o iodine and anti caking agent).

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What?

Makes sense, sort of, but in normal use the salt is used up, and there is no process for removing it and replacing with new, which is what I'd expect "flushing" to entail. One simply waits until the machine lights up the 'low salt' warning, then adds more salt up to the top.

All the tips you got regarding topping up the salt for dishwasher etc are top. here's an additional info

Light Tupperware also gets discoloured, when you place something dirty that has ketchup/brown sauce or generally tomato based food left on it, can also happen with curry dishes.

Rinsing the plates/bowls that contained this food BEFORE placing in the dishwasher helps prevent discolouring of the Tuperware too.

I handwash tupperware. I especially did when we used ones with BPA, eons ago. I still hand-wash soft plastic, color sauces get burnt on it when drying in a dishwasher, it gets manky.

This is not the issue… clearly. I had a dishwasher in Finland and we had no problem there. Never ever happened something like this before we arrived to Switzerland / Zürich.

Not to mention that for me the browning has a really characteristic mineral tone.

This is what we are doing now… but this is a change of workflow we had to do here. I was just wondering if there was any other trick we didn't know.

I know they sell dishwasher cleaner here that is sold in Migros and Coop, near the dishwasher tabs, etc. It's often used to remove any build-up of calc / limescale inside the dishwasher, so maybe that would help?

I think each of them are a bit different, but often you unscrew the cap and then put it in the silverware basket, in the machine, upside down and then run it on a high temp. But each bottle will have its own directions.

This is the one I often see sold here, and it says on the label that it's used for removing calc:

Sorry, one more thing...

You said that your machine is a Swiss brand and that the manual is only in German. Is the brand Zug, by chance? If so, Zug does also have all of their manuals available for free download online, in English, as .pdf files.

Well, there's a simple way to test if the discoloration on plastics is limescale. Get some vinegar, a piece of cloth and scrub. If the stain is gone, it's limescale, if not it's color from the food. We have at home some plastic items perennially stained with tomato sauce, very common.

What pancakes mention is true. The machine can be 10 years old or more and not cleaned that frequently. Try using a cleaning product a couple times and see if the outcome improves.

PS. a stupid joke....could all this be a indirect way your partner tells you to buy new kitchen items? Sometimes the truth is right in front of our eyes, but we nerds start thinking about water carbonate hardness instead of the simplest answer.