Dog going to the bathroom on the floor at night

Question
Why does my 4 year old dog Maltepoo pee and poop on the floor EVERY night? It doesn't matter how much I take her out, or if I take her out right before bed, she always goes on the floor at night. I constantly have to clean my carpet to neutralize the odor, and even had to replace the carpet in the house I lived before.

Recently I have noticed spots on the carpet where it looks like she has licked, and when I turned on the black light it was a urine spot. Tonight I caught her licking urine off of the carpet. I have no clue why she does this or why she doesn't let me know she needs to go outside. I even place multiple puppy pads on the floor for her. During the day I have started closing her in the kitchen, and she will use the puppy pad there.

Also, I have bells hanging from my backdoor and she will ring the bells when she needs to go outside. I have tried to use them on the bedroom door but she does not ring them to go out.  Please let me know if you have any suggestions for me. I have another dog to I adopted from my parents and he has submissive urination. But, Prissy has always behaved this way at night so I don't think having another dog around is causing her to act out.

Answer
Dogs don't generalize very well, so the fact that she is trained to ring bells at the back door doesn't translate to ringing the bell in the bedroom.  You would have to train her separately the way you did for her to ring the back door bell, to ring that bell and associate it with being taken outdoors.  It appears that she isn't completely house trained, or she would simply "hold it", so maybe you should go back to crating her at night and set your alarm to get up to take her out, and use that time to train the bedroom door bell ringing thing.  There's a good little book, called "Way to Go" that speaks to the issue of training (or, in this case, re-training) an adult dog regarding toilet issues.  If she has always done this, then the presence of a second dog is not likely the issue.  As to his submissive urination, you can help that by making all your greetings calm, not bending over him, or even ignoring him at first and then quietly greeting him.