hah thats a ***** man.
in an 8 outlet pump there will usually be 2 motors sometimes 3.
these motors are specifically designed and manufactured to pump equal amounts to each outlet- and within the motor there are those extra components there to do so. like regulatory vaulves and such.
a pump with only one outlet. although it may be able to push more water, is not manufactured to regulate the correct airflow needed for many buckets. and therefore is more insufficient when u are trying to do so.
and 8 outlet pump will show you 8 well sized aquariums- while a big 1 outlet pump will just show you one big aquarium. u see what im gettin at.
you can go buy tubes and seperators and such for not too much money. but you are going to spend much time and frustration setting them up just to realize that it will not be suffice for the entire grow.
and more than likely you will run into problems with correct air flow, simply because the pump is not designed to take into account more than one seperation. and there will most likely be inconsistancies
like i said you can do this for now. just use one pump and run seperate lines yourself to your buckets. but when your roots bust through be prepared to get more air; either that or be prepared to have problems.
if you understand the concept and have atleast seen pictures, you well know that alot of air, air pockets in your medium, and literally air bubbles are needed to maintain healthy growth.
try and set it up, and you will see for yourself. once you throw those airstones on and look at your buckets- you will immediately realize that that amount of airflow will not suffice. you dont even need anyone to tell you that. you know whats up, and you know that just a lil bit of bubbles aint gunna cut it for large root growth.
if you want, try and return it. either that or just go with it, and atleast get your plants started with it. and when the roots start growing significantly, go get more pump(s).