fpmom, we have had nothing but front-loading washing machines in our family since the late 1930s (not a typo); we have used powder detergents in them (remember Oxydol?) and tablets (remember Dash?) at various times. But, sometime in the 1980s, we switched to liquid detergents -- for the past decade at least, Biokleen All-temperature (that is the version of Biokleen without any enzymes) -- using somewhat less detergent than the recommended dosage, but supplementing the detergent with a scoop (about 1/4 to 1/3 cup) of borax per load. I cannot remember why we switched back then, but I can say that we do not plan on going back to powders; for our water conditions (soft city water), we are in a "sweet spot," and cannot imagine switching.

thanks herring_maven
How does water hardness affect powder or liquid?
I checked our water and apparently it is halfway between hard and soft
The reason I am asking these questions is the problem I have had with mold in the washer (a new 8 mth old machine) - I am getting the machine replaced and want to ensure I do everything I can to prevent this happening again (despite the fact I have used FL's the last 20 years with no issues previously - I am not new to the 'scene'!)

fpmom: "How does water hardness affect powder or liquid? ... The reason I am asking these questions is the problem I have had with mold in the washer ..."

The detergent must dissolve into the wash water before it an be effective, and soft water will allow the detergent to dissolve more readily than hard water, which already has minerals dissolved in it. Liquid detergents are already dissolved in an aqueous solution, and merely need to be diluted by the wash water. My first guess from the data that you have provided -- 20 years of use with no mold problem, but now mold with a newer washing machine -- is that you may not have dialed back sufficiently on detergent quantity per load when you acquired a machine that uses significantly less water per load than previously. Have you tried reducing your dosage even further?

Herring_Maven I think that is why I went to liquid to start with (in Australia always used powder) because I use cold water in a lot of washes and the cold water in winter is VERY cold in New England lol so I thought it might not dissolve the powder adequately
Re the amount I use - I actually use LESS now than I did when living in Australia (in Australia used Bosch and Asko FL with absolutely no issue and also used fabric softeners) ... I use 1Tb of Charlie's soap liquid (you measure with the container so always the same amount) with vinegar in the rinse cycle - NO fabric softeners etc... the water is midway between hard and soft but I use a water softener from Charlies Soap to ensure no issue with hardness
The only other thing I can think of is that in Australia we did not have humidity where i lived and is a very dry heat in summer - I also don't usually use hot water but never did in Australia either (and no issues) though I have recently changed due to dust mite allergies (which is a new thing for me) and now do a few sanitise loads per week which I am guessing will be good for the new machines I change for since that should help prevent the mold problem