Water – How to prevent white film forming on utensils in dishwashers


I've installed a Bosch SMS60L18IN dishwasher, best in its latest series. We were very satisfied with its first wash when it gave us clean utensils without any problems. We put a 3 in 1 tablet then. Now, I use a special salt, detergent and rinse aid, all from Finish.

From the second wash onward, it leaves white film on almost all utensils and food residues are not cleaned on some.

I tried all workarounds that I found online like changing detergent amounts and using the vinegar trick.

The issue I was thinking and the company engineers suspect is the water hardness which is around 900 (or 920) ppm. They changed the hardness level in the machine to H7 (this is the max one for 8.9 mmol/L hardness that the company specified) suggested me to run the machine for a few cycles to get rid of water residue from previous cycles.

I've already ran four cycles and the issue still persists. Is the water hardness the cause alone? Would be there other issues like the detergent or salt?

I observed:

  1. The first wash was perfect. We haven't used salt here. Second and
    third washes are a bit okay.
  2. In the second wash. We put a 1.5 kg of specially recommended salt (Finish brand)
  3. Issue worsened from the fourth wash.
  4. I realized that I haven't filled the salt reservoir with water (the company recommends to fill it with water when you use the machine for the first time) and then filled it with a glass of water.
  5. The technicians said that is not a big issue as the machine will itself dilute the salt with water after 2 or 3 washes.
  6. I ran the machine by pouring a cup of vinegar as suggested in some articles and I found that the white layer on the machine's door was gone and utensils in the next wash are somewhat clean. Also, I tried changing detergent amounts, rinse aid quantity settings and switching hardness levels with each wash.

  7. Tried changing the size of the load with each wash

  8. Even if we purchase a budget softener like this, it may have low output rates and that gives new problems.

  9. importantly is that it's too noisy (it gives knocking sounds while rinsing) like a clothes washing machine. The company staff said it is normal or I guess it is not that loud when they are around:)

More details

  • Name of the detergent, salt and rinse-aid's brand is Finish
  • I am not using all-in-one tablets now

The company staff recommended water softeners (of a different brand as they don't sell softeners). But I fear if it brings new issues like the change in flow rate (individual tap softeners have low flow rate, i.e., 2 litres per minute where as the dishwasher requires 6 litres per minutre). Ours is a rented house so I can't install a permanent or full house water softener.

Could anybody tell me if you find any other issues here other than the water hardness? Any suggestions or solutions are welcome.

Best Answer

is it wise to spend on dishwasher maintenance and water softeners when we have the water with too much hardness (900 ppm)?

Well, the whole point of a water softener is to reduce the hardness. So I find it odd that you ask if it's wise to use a water softener when your water is excessively hard... In short, yes, that's what you do to fix this problem, normally - install a water softener with appropriate capacity to deal with the hardness of your water, at least for the appliances you care about that for.