Plumber several times and nothing seems to help. If I'm washing something or brushing and flushing, the sink is full. Then it takes probably 15 minutes to drain. A friend of mine told me to put hydrogen peroxide on it. This helped somewhat, but in a very short time, slowed again. I even put two bottles of peroxide once. Well, I have the answer here. Try CLR Power Plumber brand, it's just a can of air you have over the drain opening and push down on the can. I've used it many times in different applications and has always worked very well. I bought it at ACE hardware store but I'm sure it is available anywhere.
This is the second part of a video on how to install pex pipe in your home. Included is the real beginning of the pipeline, along with some advice for me. . .