Dishwasher leaving dirty marks on china

Causes

• You have only used a short cycle, which has not been sufficient to clean your dishes.  This type of programme is generally for glasses, mugs and tea plates.  It is advisable to use a longer programme when you have had your main meal, as there is likely to be baked-on debris on your dishes, which will require a longer time to clean
• Too low water temperature – this is exactly the same as the point above.  Only use your low temperature cycles for very lightly soiled dishes
• Old or badly store detergent – as with most things in life, dishwasher detergent does not improve with age, especially if you store it at very low temperatures, or where there is the possibility of ingress of damp.  Make sure you use your detergent in strict rotation, oldest product first.  This should help to avoid this problem
• Poor quality detergent  You only get what you pay for is very true, especially with dishwasher detergent.  It is a false economy to pay out for the dishwasher  and then expect it work properly if you only use budget detergent.  Try to get the best product you can afford, otherwise you will increase your electricity bill by having to rewash your dishes.  Always go for a well-known brand, and by process of elimination you will find the right kind of detergent which is the best for your appliance.
• Food residue trapped in the filters.  As part of your normal cleaning routine for the inside of your appliance, you should regularly check that the filters are clear of debris.  Just remove them from the bottom of your dishwasher, take apart as required, and clean thoroughly under a running tap.  This will dislodge any trapped debris, which will avoid this debris being transferred to your dishes during the wash cycle
• Incorrect loading.  Believe it or not there is a correct way to load a dishwasher, and if you check in your manufacturer’s manual you will see some very handy tips of what should go where.  In essence, do not overload it, do not let dishes touch against one another, as once the machine is in operation, the vibrations can cause the dishes to close the gaps and not allow water or detergent to get to each item.   Do not cram too many items of cutlery in the basket and try mix them up so you don’t always have same items together.  Knives should be washed point down, all other items to be washed pointing up.
• Adding items during a cycle.  Once you have switched on the dishwasher you can turn round and see an item you have forgotton.  As long as you add this straight away there should not be a problem, however, if the cycle has been running for quite a while, adding another item can contaminate the whole load.
• Blocked spray arm.  Again, during your regular cleaning routine, it is a good idea to remove the arms and check they are not blocked.  Running them under the tap should help you to spot and clear a blockage.
• Obstructed spray arm.  If you are loading extra large plates or longer cutlery than usual, before switching on the dishwasher, spin the arms to make sure they can turn properly.  You should be able to hear a knocking once the appliance is working if there is an obstruction.  You should stop the machine and remove the offending item straight away, otherwise the cycle will be wasted as insufficient water and detergent will be sprayed around the machine.

Hopefully this has helped solve any problems similar to this, but regular cleaning of the dishwasher is a very good idea and will help to keep your appliance working for a long time.