Slow bathroom drainage.

[Bonefish Blues]

I've already recommended a plunger. V quick and brilliantly effective. Maybe not in all cases, but seems reasonable as a starting point.

@Fastpedaller gives some technique suggestions above.

There's a point where my plunger (the water-squirty type) needs to be supplemented with chemistry, but I take your general point about an escalating approach.

 

[Dogtrousers]

There's a point where my plunger (the water-squirty type) needs to be supplemented with chemistry, but I take your general point about an escalating approach.

Yes, plunging is always my default approach. I don't consider a sink "blocked" or "slow draining" unless I've given it a good plunging and it's still bad. That's when I reach for the chemicals.