Solar iboost secondary output

[bigspark17]

I have fitted iboosts to single immersion circuits before but now have a job with two cylinders.
Isit just a case that once the first output is satisfied it will just move on to the next output?
Can you decide which output to boost on the iboost?
The second tank is about 20m ish away, i seem to recall the iboost needs to be situated close to the tank.

Thanks