Here we go again....would really like to be helpful, but.........

"I fill the cup to line #1 (which is the bottom line) "

WHAT cup? How much are you using? Tablespoons or measuring cups would be fine....just something so a cyber-stranger can tell how much you're talking about.

"Whirlpool Duet FL "

What year? What model? Please? They've made them in a number of different sizes/configurations.

"Normal size load"

Would appreciate weight or cubic feet or something what would allow a cyber-stranger to have some clue as to what "normal size" means to you. For example, if you have a 3.8cf machine and say you load it loosely to the top without stuffing/compression, I can tell you've got maybe 18 lbs. or so of fabric in there.....but you've got to give us something, don'cha think?

"Warm wash/Cold rinse"

Do you know what the actual temperatures are or are you just setting the dial to "warm" and "cold" and walking away ? The difference between what people actually have and what they think they have can be HUGE.

Do you know what your water quality is....as in soft or some degree of hardness?

"Does this mean I'm using too much detergent?"

Probably.

How long have you owned the machine? Could be residual left in the clothes, too.

Since OP says they are using Tide I "assume" she is talking about line 1 on the cap (makes sense to me).

I had a Frigidaire FL pair for 10 years. I often had problems with residual suds left on the seal/bottom of glass after the final rinse.

When I got my new Miele W4842 in Feb of this year I never had that problem (well once or twice and it was my fault for using too much detergent).

I'm no engineer but I feel that the difference is in the way my Miele rinses. I feel it rinses much better than my previous Frigidaire did.

That doesn't really help you I know. Problem is you don't want to use too little detergent and not get things clean but you want them to be well rinsed.

Does your machine offer an extra rinse cycle? I always use the sensitive setting on my Miele which always gives me a faster interim spin and an extra rinse (3 instead of 2).

Yes, Here we go again...Thanks asolo for reminding me why I quit using this website.

Livebetter, I'll try an extra rinse.

@pawprint1, I stopped using Tide HE liquid - I think it doesn't rinse well. Try switching detergents and see if that makes a difference. I find that powders generally rinse better, so you could try Tide HE powder, if you like Tide. I have powder Tide HE w/bleach and it works really well. I also like Sears powder detergent and Cheer powder. And like livebetter, I also like using an extra rinse with all my cycles. My LG is such a water miser that even with an extra rinse, it is still very water efficient.

Keep in mind that if inadequate rinsing is an issue then you may have some detergent residue in your clothes that will take time to remove, so you may not see an immediate improvement even when you switch detergents.

"Thanks asolo for reminding me why I quit using this website."

Would have preferred to be helpful but more-or-less impossible with the little information you provided. Don't know why you'd be miffed at someone asking for more than than the useless "facts" you provided.

"....I'll try an extra rinse."

So you're saying you never thought of that on your own? Interesting.

FWIW, I have a Duet FL that has worked flawlessly for over six years with all different load sizes, types, and temperatures. It may or may not be like yours but I have every reason to believe I may have been helpful.....if you'd provided any meaningful information. I mistakenly thought you might be wanting actual information and advice...which you would likely get if you gave anyone a handle.

IMO, folks on this board tend to be alarmist about sudsing.

If there's no obvious excess sudsing in the wash or rinse(s), laundry is coming out of the machine cleaned per your satisfaction, and you're not having an allergic or olfactory reaction to detergent residue ... then seems to me that you're golden.

Load size is difficult to quantify. I've noticed a huge range in what people consider to be a "small" or "normal" or "large" load. I recall someone stated that he/she washes 5 to 7 shirts per "average" load. I ran a load of 17 shirts + a few other items recently in an agitator toploader (rated at 8 kg or 17.6 lbs), which was a nicely-full load. I used a full measured cup (8 oz) of Foca powdered detergent and had no sudsing in the wash.

I've used Tide HE powder and Coldwater liquid, Gain HE powder, and Wisk HE liquid in my HE machines ... up to a full stated dose for a large load (3/4 cup of HE powder or line 3 on the cap for HE liquid), and have no trouble with rinsing ... even if there is some sudsing in the wash.

To get a feel of whether a detergent really is difficult to rinse in one's specific water conditions ... handwash an item (using an appropriate, proportionately smaller dose of detergent) and take notice of how the rinsing goes.

@ pawprint1

Please don't be discouraged by the small minority of people here who feel they need to reaffirm their own [insert noun of choice] by insulting and berating others. The more sane among us know what you're asking, and we can definitely relate to your concern. And we most certainly know what "cup" you are referring to... Some people are unbelievable, aren't they?

Basic answer is this... if you are seeing suds in your rubber boot/gasket after the cycle is complete, you are probably using too much detergent. I think Tide HE liquid detergent is the offender. I find that it suds way too much, even with small quantities. You may not see the suds during the wash due to the small amount of water, but rinsing typically uses more water and tends to suds up because of increased agitation of the water.

I would recommend trying Tide HE powdered detergent, starting with about half the quantity recommended by the detergent manufacturer. Adjust up or down as needed. Tide HE Total Care does not suds much, and it makes your clothes feel nice. It's more expensive, but you might want to give it a try.

Right....sshrivastava with her usual clairvoyance weighs in with everything one needs to know....notwithstanding that she has near-zero information from which to form any meaningful opinion at all.

Typical.

Carry on, all. Happy to stay out of it.