I run dual HOBS along with sponges(air driven) on all my grow out tanks.
2@ aquaclear 70 on a 55g(with 2 large sponge)
2@ Aquaclear 50 on a 33 long(with 2 sponges)
2@ aquaclear 110 on a 75g(with 2 sponges)
and so on!(not up to 400 g of breeders yet!For real).
These are all for GBR so current shouldn't be a concern for many other fish IMO
They only need to be primed if you let evaporation lower the water level too much or leave them running like mentioned during wc
Keep up on your tank man!!!
I have extensions for all the AQ intakes I ordered from kens(good deal on filters and food).
Aquaclear Filter Parts
All dry goods can be found cheaper online !