Powders...
In my machines I use powders, powders, and more powders. Use of liquid detergent is punishable by deas (which is remarkably similar to death).
I put in the detergent first, then the clothes, then start the machine. Even if the powder doesn't dissolve, it is down near the agitator fins and gets swished into submission quickly. I have never had a problem, even in cold water. Sometimes, I will start the fill after adding the detergent and then add clothes as the washer fills. I will also sometimes start the fill hot and then switch to cold or warm later. If the powder doesn't dissolve, chack to make sure the machine isn't overloaded.
I have used Tide powders and tend to like them, but I also use Cheer Original powder, Gain Original Powder, Foca, Roma, Fresh Start, and a few others.
Powder is cheaper per load and the boxes make handy washer and dryer lint trash cans.
Dave