Code:
"?"....you lost me on that one.
The sump is where the pump is. (PIST)
Most people refrain from 'pumping' solids. In gravel GB's, it would be OK. Even then, you increase the chance, your pump 'might 'plug.
But with NFT, DWC, towers, or continous flow, like my set up, I wouldn't want to be pumping solids. It breaks them up, then it's even harder to remove. One would be trying to remove them 'first'.
Preferably..the sump is called a sump because it catches all the goop (poo) etc. in their case, it is the clarafier as they called it.
Once the goop has been removed after having transversed the sump slowly enough to allow all particles that will, to drop to the bottom to be flushed out from the bottom as she shows in the video when describing the clarifier.

Once the goop is removed, then is when the water should go to the bio-filter to make all the changes to the nitrites etc. and that's where I have always placed my pump...to pump the water to the GB.

According to how the system is set up, how many pumps you are using, where the FT is located, above - below - same lever as Sump (clarifier) - GB - bio-filter.

There are so many ways to set up a system, but all the components regardless of whether they are above, below or same level as the GB....they have to follow in a manner that allows for the water to flow from the fish to the sump, then the bio-filter and from there to the GB and then back to the fish clean of goop and clear of ammonia, nitrites and nitrates.