I recently got 99 slayer and now I need a bit of cash and crimsons for 99 summoning. Waterfiends are boring so I thought why not camp Abby Demons and make money towards 99 summoning.

 

1.) Should I piety? I'll be using heaps of prayer pots but it will speed up kills and might profit long term.

 

2.) What does camping abby demons come to in the long term money per hour wise.

1) Na, Turmoil is much better, but piety can help too.(obviously)

2) Assuming all the random drops cover your potion cost(which is about right), 1/600 per whip, 200 an hour, so the hourly profit should be somewhere between 1-1,3m(assuming turm, ext, rapier).

 

Apart from that, camping abyssal demons is not an efficient thing to do. Sure, training slayer with blocks/cancels is narrowly beaten by it(in terms of profit and charms) but i'm 100% sure a combination CT wtf's + DK/TD/frost will easily beat it in overall efficiency by quite a bit(waterfiends being 3x the charms, moneymakers 3x the money).