Any idea why the dirty water gets backed into my dishwasher

I do notice my dishwasher outlet is going into the garbage disposal. I am assuming when water accumulate in the garbage disposal is flowing back into dishwasher. I have to run the dishwasher and cancel the cycle so it drains this dirty water from dishwasher. Plus the water smells horrible. Is my dishwasher faulty or the dishwasher outlet should be going into the other drain from the sink??

Attached a new sink to existing pipes

Glycol Valves are showing these blue tinges. How do we fix it?

I think it’s glycol

Please help me find this

I need help. I work at a museum. An exhibit uses these 1"-9 plastic lengths of all thread... probably a foot long. I've also looked for m25x3mm. Needs to be about 10+ inches long. Can't find either.

Can I use this bottom cap for my gas stove ?

I want to run a gas line up to my kitchen for my stove. Is this bottom pipe with a cap there for any reason. Can I remove the cap and run my gas line for the stove off of the bottom pipe??

How screwed am I?

Trying to replace a gross old bath tub drain. The plumbers wrench broke the crosshairs, so I went and got an extraction tool. It managed to break away the top, but leave the threaded body of the old drain still down there. Any way to get it out?

American standard champion flush valve

My flush valve is leaking and causing my toilet to run. Can I replace it with a fluidmaster flush valve or does it have to be the same one in the picture?

Does this valve just screw off and I replace it or do I have to replace the whole system

I've tried looking at hardware stores sites and can't seem to find something that looks similar to replace it with

What type of valve is this?

The valve for my countertop water dispenser leaks, and I'm having trouble looking up a replacement. What should I search for to find this part? It works by opening when the chrome handle pushes down on the white button.

How do I replace this accordion pipe? Should I call a plumber (no plumbing experience)?

Please help me identify this plug waste thread. It's 16 years old & made in China. It's about 36.5 mm OD and about 17 threads per inch.