Vinegar (mild acid) can reduce fabric harshness if there's residual alkalinity from detergent but vinegar does not contain fabric lubricants as does softener.

Optical brighteners are not bleach. They make whites and light colors appear brighter by absorbing UV light and emitting blue-violet light (minimizing yellow-ish light reflection), resulting in a similar effect as laundry bluing.

Best additive for hard water (if there's no whole-house mechanical softener system) is a non-precipitating chemical softener such as STPP (sodium tripoly phosphate), which is the complex phosphate that were removed from detergent years ago.

First: Be sure to turn the 'Maximum Rinse Level' in the programmable settings. This will improve rinsing quite a bit. It explains how to do this later on in the manual.

Second: Since you have hard water, I highly recommend using a more powerful detergent that will be able to cope with your water hardness. Be sure you aren't using a 'detergent' that may cause buildup (detergent or mineral) and ruin the machine you just purchased. As dadoes stated, STPP is a great way to help combat this.

Third: I highly recommend a detergent containing enzymes. My personal recommendations would be either Tide Advanced Oxi (Costco) or Persil Oxi. Both can deal with hard water, clean really well, and can be dosed at a lower quantity without too many issues. The Persil does not have as strong of a scent compared to the Tide.

Skimping on detergent in a hard-water situation increases mineral and soil residue in the washer since much of the detergent ingredients are caught-up in the water hardness and less is available to deal with the laundry soils. A slippery feel between fingers rubbed in the wash water is an indication that water hardness is properly handled.

Over-rinsing can be a factor of causing mineral residue in hard-water situations, leaving deposits on internal washer parts when the residual water evaporates (including where rotating drive shafts meet rubber seals).

In my Miele, I use Tide Free and Gentle liquid. It's a wonderful, low sudsing detergent that does not contain any optical brighteners. I get perfect results using just under 2 tablespoons per load witrh the maximum rinse level enabled. I also turned on the allergy setting so most cycles get an extra rinse.

If your looking to use as little detergent as possible, buy a TwinDOS model. I don't think you will regret it.

In CR's tests, Tide Free & Gentle did not perform well enough to earn a recommended rating. Persil Free & Sensitive did earn a recommended rating and is available at Walmart.

I have crazy dry, crazy sensitive skin. I use Charlie's Soap as my detergent and add a heaping tablespoon of citric acid powder and some white vinegar where you are supposed to put fabric softener. With the Charlie's Soap, I add in some borax and some STTP. This all works pretty well for most loads. I add some Oxiclean White Revive for white loads.

The vinegar and citric acid powder work great and do absolutely no harm. I use them for a final rinse of my hair as well. They work great for that too.

It recently came to my attention that borax is precipitating for water softening functionality. STPP is non-precipitating. Borax has other benefits than just water softening but I'm not enough of a chemist to know whether it clashes with STPP on that point, or how the dosage should be arranged if both are used.

For liquids and powder Ive standardized on Persil. I refill the W1's cartridges with off the shelf persil.