I plan to switch my angels into my 40 breeder after they grow out, However I know the angels need low flow and I would prefer sponges but I do not know how big of sponges they make or if there are alternatives.
The largest Hydro is rated for 125 gallons. Its size will take up a sizeable area though. I am not aware of any benefits of more filtration, beyond what will handle things for the tank size, filter and fish species and number.I need something rated for 100 + gallons with low flow. I always run at least double filtration