From babysitting Julie, Zoe made 3 * 600 = <<3*600=1800>>1800 dollars, since she made $600 babysitting Zachary and she babysat Julie three times as often
Since she babysat Zachary 1/5 as often as she babysat Chloe, she made an additional 5 * 600 = <<5*600=3000>>3000 dollars from babysitting Chloe.
All together, the babysitting sessions made Zoe 600 + 1800 + 3000 = <<600+1800+3000=5400>>5400 dollars
Subtracting babysitting payments from the total gives 8000 - 5400 = <<8000-5400=2600>>2600 dollars
Zoe therefore made 2600 dollars cleaning pools.
#### 2600