haier HDT18PA - Manual (Page 11)

Use proper recommended amount of detergent for your wash loads.
Pour in detergent into open compartment that is located on the inside of the door.
Pouring Dishwasher Detergent:
The amount of detergent to use depends on the type of water in your living area
whether it is hard or soft and whether items are lightly or heavily soiled.
Water softness or hardness is measured in grains content per gallon. You can find
out grains level by calling your local Environmental Protection Agency (EPA) in your
county.
If you find that "grains" level is higher in the water then the water will be harder in
your living area so you will need more detergent to clean. If "grains" level is lower
then the water will be softer in your living area so you will need less
detergent to clean.
Proper Use of Detergent:
See the following table to understand the "water hardness type" and "grains" level.
Note: If "grains" level is over 12 then water is very hard. You may need water softener
to improve the water quality and the performance of your dishwashing.
Note: The quality of detergent will make the big difference of cleaning your dishes.
If you are using detergent that is damp, clumsy or too old then this type of
detergent will not be as effective to clean because of active ingredients are
phased off and the detergent will not work properly.
Water Hardness Type Level of Grains in the water
Hard 10+
Medium 4-9
Soft 0-3
10
GB