Hi dentists. can i mix my water pik water with mouthwash or is just water better? cold water, warm water, or hot water?

Most if not all of your questions regarding product use can be obtained by reading your models online instruction guide: https://www.waterpik.com/oral-health/product-support/manuals/ Temperate water should be just fine.

USE WARM WATER THAN RINSE AND BRUSH YOUR TEETH WITH A SOFT BRUSH. AFTER BRUSHING USE A GUM STIMULATER AND THAN FINISH WITH MOUTHWASH. GOOD ORAL HYGIENE WILL KEEP YOUR TEETH FROM DECAY AND GUM DISEASE.

Justplan room temperature water for longest appliance life.